The expression of microRNAs and exposure to environmental contaminants related to human health: a review.

Environmental contaminants exposure may lead to detrimental changes to the microRNAs (miRNAs) expression resulting in several health effects. miRNAs, small non-coding RNAs that regulate gene expression, have multiple transcript targets and thereby regulate several signalling molecules. Even a minor alteration in the abundance of one miRNA can have deep effects on global gene expression. Altered patterns of miRNAs can be responsible for changes linked to various health outcomes, suggesting that specific miRNAs are activated in pathophysiological processes. In this review, we provide an overview of studies investigating the impact of air pollution, organic chemicals, and heavy metals on miRNA expression and the potential biologic effects on humans.Abbreviations: AHRR, aryl-hydrocarbon receptor repressor; AHR, aryl-hydrocarbon receptor; As, arsenic; BCL2, B-cell lymphoma 2; BCL2L11, B-cell lymphoma 2 like 11; BCL6, B-cell lymphoma 6; BPA, bisphenol A; CVD, cardiovascular diseases; CD40, cluster of differentiation 40; CCND1, Cyclin D1; CDKN1A, cyclin-dependent kinase inhibitor 1A; Cr, chromium; CTBP1, C-terminal binding protein 1; CXCL12, C-X-C motif chemokine ligand 12; DAZAP1, deleted in azoospermia associated protein 1; DEP, diesel exhaust particles; EGFR, epidermal growth factor receptor; eNOS, endothelial nitric oxide synthase; EVs, extracellular vesicles; FAK, focal adhesion kinase; FAS, fas cell surface death receptor; FOXO, forkhead box O; HbA1c, glycated hemoglobin; Hg, mercury; HLA-A, human leukocyte antigen A; HMGB, high-mobility group protein B; IFNAR2, interferon alpha receptor subunit 2; IL-6, interleukin-6; IRAK1, interleukin 1 receptor associated kinase 1; JAK/STAT, janus kinase/signal transducers and activators of transcription; MAPK, mitogen-activated protein kinase; miRNAs, microRNAs; MVs, microvesicles; NCDs, noncommunicable diseases; NFAT, nuclear factor of activated T cells; NFkB, nuclear factor kappa B; NRF2, nuclear factor, erythroid-derived 2; NRG3, neuregulin 3; O3, ozone; OP, organophosphorus pesticides; PAHs, polycyclic aromatic hydrocarbons; Pb, lead; PCBs, polychlorinated biphenyls; PDCD4, programmed cell death 4; PDGFB, platelet derived growth factor subunit beta; PDGFR, platelet-derived growth factor receptor; PI3K/Akt, phosphoinositide-3-kinase/protein kinase B; PKA, protein kinase A; PM, particulate matter; PRKCQ, protein kinase C theta; PTEN, phosphatase and tensin homolog; SORT1, sortilin 1; TGFß, transforming growth factor-ß; TLR, toll-like receptor; TNF, tumor necrosis factors; TRAF1, tumor necrosis factors-receptor associated factors 1; TRAP, traffic-related air pollution; TREM1, triggering receptor expressed on myeloid cells 1; TRIAP1, TP53 regulated inhibitor of apoptosis 1; VCAM-1, vascular cell adhesion molecule 1; VEGFA, vascular endothelial growth factor A; XRCC2, X-ray repair cross complementing 2; YBX2, Y-box-binding protein 2; ZEB1, zinc finger E-box-binding homeobox 1; ZEB2, zinc finger E-box-binding homeobox 2; 8-OH-dG, 8-hydroxy-guanine.

Graphene Confers Ultralow Friction on Nanogear Cogs.

Friction-induced energy dissipation impedes the performance of nanomechanical devices. Nevertheless, the application of graphene is known to modulate frictional dissipation by inducing local strain. This work reports on the nanomechanics of graphene conformed on different textured silicon surfaces that mimic the cogs of a nanoscale gear. The variation in the pitch lengths regulates the strain induced in capped graphene revealed by scanning probe techniques, Raman spectroscopy, and molecular dynamics simulation. The atomistic visualization elucidates asymmetric straining of CC bonds over the corrugated architecture resulting in distinct friction dissipation with respect to the groove axis. Experimental results are reported for strain-dependent solid lubrication which can be regulated by the corrugation and leads to ultralow frictional forces. The results are applicable for graphene covered corrugated structures with movable components such as nanoelectromechanical systems, nanoscale gears, and robotics.

Fibronectin/thermo-responsive polymer scaffold as a dynamic ex vivo niche for mesenchymal stem cells.

In this paper, we created a dynamic adhesive environment (DAE) for adipose tissue-derived mesenchymal stem cells (ADMSCs) cultured on smart thermo-responsive substrates, i.e., poly (N-isopropyl acrylamide) (PNIPAM), via introducing periodic changes in the culture temperature. We further explored the particular role of adsorbed fibronectin (FN), an important cell adhesive protein that was recently attributed to the recruitment of stem cells in the niche. The engineered FN/PNIPAM DAE system significantly increased the symmetric renewal of ADMSCs, particularly between passages 7 and 9 (p7-p9), before it dropped down to the level of the control (FN-coated TC polystyrene). This decline in the growth curve was consistent with the increased number of senescent cells, the augmented average cell size and the suppressed FN matrix secretion at late passages (p10-p12), all of them characteristic for stem cells ageing, which equivocally tended to slow down at our DAE system. FN supported also the osteogenic response of ADMSCs (apart from the previous observations with plain PNIPAM substrata) indicated by the significant increase of alkaline phosphatase (ALP) activity at days 7 and 14. The minimal changes in the Ca deposition, however, suggest a restricted effect of DAE on the early osteogenic response of ADMSCs only. Thus, the engineering of niche-like DAE involving FN uncovers a new tissue engineering strategy for gaining larger amounts of functionally active stem cells for clinical application.

Free-Standing Graphene Oxide and Carbon Nanotube Hybrid Papers with Enhanced Electrical and Mechanical Performance and Their Synergy in Polymer Laminates.

Hybrid nanomaterials fabricated by the heterogeneous integration of 1D (carbon nanotubes) and 2D (graphene oxide) nanomaterials showed synergy in electrical and mechanical properties. Here, we reported the infiltration of carboxylic functionalized single-walled carbon nanotubes (C-SWNT) into free-standing graphene oxide (GO) paper for better electrical and mechanical properties than native GO. The stacking arrangement of GO sheets and its alteration in the presence of C-SWNT were comprehensively explored through scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. The C-SWNTs bridges between different GO sheets produce a pathway for the flow of electrical charges and provide a tougher hybrid system. The nanoscopic surface potential map reveals a higher work function of the individual functionalised SWNTs than surrounded GO sheets showing efficient charge exchange. We observed the enhanced conductivity up to 50 times and capacitance up to 3.5 times of the hybrid structure than the GO-paper. The laminate of polystyrene composites provided higher elastic modulus and mechanical strength when hybrid paper is used, thus paving the way for the exploitation of hybrid filler formulation in designing polymer composites.

The effect of a postural exercise program on muscle power in Italian high school students.

[Purpose] The present study aimed to investigate the effect of an innovative postural program (the Canali Postural Method, CPM) on muscle power in Italian high school students. It is note that deficits in posture control may, in long term, generate posture weakness as early as childhood and adolescence. Postural programs based on stretching and strengthening exercises can remove these deficits and can be framed in general physical or sport activities. [Participants and Methods] Thirty-four students completed a 8-week postural program. The intervention, consisting of stretching and muscle activation exercises, was integrated in physical education lessons. For the evaluation of the effect of CPM program, we have used the countermovement jump (CMJ), a simple and versatile test that measures muscle power. [Results] The CPM program resulted in significantly increased vertical jump height of the students. The average difference between Initial and Final CMJ was 2.1 cm. [Conclusion] This finding indicates the benefic effect of this new postural program on physical performance in the youth. Further randomized control trials should be conducted to evaluate CPM long-term implications in the prevention of posture weaknesses and its inclusion in the regular school curriculum.

Standardized languages and notations for graphical modelling of patient care processes: a systematic review.

PURPOSE: The importance of working toward quality improvement in healthcare implies an increasing interest in analysing, understanding and optimizing process logic and sequences of activities embedded in healthcare processes. Their graphical representation promotes faster learning, higher retention and better compliance. The study identifies standardized graphical languages and notations applied to patient care processes and investigates their usefulness in the healthcare setting. DATA SOURCES: Peer-reviewed literature up to 19 May 2016. Information complemented by a questionnaire sent to the authors of selected studies. STUDY SELECTION: Systematic review conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. DATA EXTRACTION: Five authors extracted results of selected studies. RESULTS OF DATA SYNTHESIS: Ten articles met the inclusion criteria. One notation and language for healthcare process modelling were identified with an application to patient care processes: Business Process Model and Notation and Unified Modeling Language™. One of the authors of every selected study completed the questionnaire. Users' comprehensibility and facilitation of inter-professional analysis of processes have been recognized, in the filled in questionnaires, as major strengths for process modelling in healthcare. CONCLUSION: Both the notation and the language could increase the clarity of presentation thanks to their visual properties, the capacity of easily managing macro and micro scenarios, the possibility of clearly and precisely representing the process logic. Both could increase guidelines/pathways applicability by representing complex scenarios through charts and algorithms hence contributing to reduce unjustified practice variations which negatively impact on quality of care and patient safety.

Effects of working from home on lifestyle behaviors and mental health during the COVID-19 pandemic: A survey study.

The COVID-19 outbreak has led to relevant changes in everyday life worldwide. One of these changes has been a rapid transition to and an increasing implementation of working from home (WH) modality. This study aimed to evaluate the impact of mandatory WH during the COVID-19 pandemic on lifestyle behaviors, Mediterranean diet adherence, body weight, and depression. An online cross-sectional survey was conducted in the early 2022 at the National Research Council of Italy using ad hoc questions and validated scales collecting information on physical activity, sedentary behavior, hobbies/pastimes, dietary habits including adherence to the Mediterranean diet, body weight, and depression during WH compared with before WH. 748 respondents were included in the study. An increased sedentary lifetime was reported by 48% of respondents; however, the subsample of workers who previously performed moderate physical activity intensified this activity. Body weight gain during WH was self-reported in 39.9% of respondents. Mediterranean diet adherence increased (p≪0.001) during WH compared with before WH. The average level of mental health did not record an overall variation; however, the proportion of subjects with mild and moderate depression increased (p = 0.006), while workers who reported values indicative of depression before the transition declared an improvement. These findings highlight health-related impact of WH during the COVID-19 pandemic that may inform future strategies and policies to improve employees' health and well-being.

MIR-29A-3P, MIR-29C-3P, MIR-146B-5P AND MIR-150-5P, Their Target Genes and lncrnas in HIV Infection: A Bioinformatic Study.

INTRODUCTION: Increasing evidence suggests that microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) have emerged as attractive targets in viral infections, including Human immunodeficiency virus (HIV). OBJECTIVE: To deepen the understanding of the molecular mechanisms that lead to HIV and provide potential targets for the future development of molecular therapies for its treatment. METHODS: Four miRNAs were selected as candidates based on a previous systematic review. A combination of bioinformatic analyses was performed to identify their target genes, lncRNAs and biological processes that regulate them. RESULTS: In the constructed miRNA-mRNA network, 193 gene targets are identified. These miRNAs potentially control genes from several important processes, including signal transduction and cancer. LncRNA-XIST, lncRNA-NEAT1 and lncRNA-HCG18 interact with all four miRNAs. CONCLUSION: This preliminary result forms the basis for improving reliability in future studies to fully understand the role these molecules and their interactions play in HIV.

The medium-term perceived impact of work from home on life and work domains of knowledge workers during COVID-19 pandemic: A survey at the National Research Council of Italy.

Objective: The study aimed to investigate perceptions and determinants of the overall impact on life and work domains among a community of knowledge workers after 18 months of forced work from home due to the pandemic. Methods: A cross-sectional study with a retrospective assessment was conducted early in 2022 at the National Research Council of Italy. Five single-item questions explored the perceived impact on life domain while a 7-item scale the impact on the work domain. Bivariate analyses and multivariate regressions were used to evaluate the associations between impacts and some key factors defined by 29 ad hoc closed questions. Results: More than 95% of the 748 respondents reported a perceived change in at least one item of the life domain. For each of these items, although a large group of subjects has reported that working from home had no impact (from 27 to 55%), in the rest of the sample the positive evaluation (from 30 to 60%) clearly prevailed over the negative one. Overall, most of the subjects (64%) rated the impact on the work experience positively. Relationship with colleagues and participation in the work context were the items where the greatest number of negative rates was concentrated (27 and 25%, respectively). On the other hand, positive perceptions prevailed over both negative perceptions and lack of impact perceptions on the subjects of organizational flexibility and quality of work. The frequency of work-room sharing, home-work commute time and changes in sedentary lifestyle, have been identified as common explanatory factors of perceived impacts on both domains. Conclusion: Overall, respondents reported positive rather than negative perceived impacts of forced work from home in both their lives and work. The obtained results suggest that policies to promote the physical and mental health of employees, strengthen inclusion and maintain a sense of community are necessary to improve workers' health and prevent the effects of perceived isolation on research activities.

Corrigendum: The medium-term perceived impact of work from home on life and work domains of knowledge workers during COVID-19 pandemic: a survey at the National Research Council of Italy.

[This corrects the article DOI: 10.3389/fpubh.2023.1151009.].

Congenital anomalies among live births in a polluted area. A ten-year retrospective study.

BACKGROUND: Congenital anomalies and their primary prevention are a crucial public health issue. This work aimed to estimate the prevalence of congenital anomalies in Brindisi, a city in southeastern Italy at high risk of environmental crisis. METHODS: This research concerned newborns up to 28 days of age, born between 2001 and 2010 to mothers resident in Brindisi and discharged with a diagnosis of congenital anomaly. We classified cases according to the coding system adopted by the European Network for the Surveillance of Congenital Anomalies (EUROCAT). Prevalence rates of congenital anomalies in Brindisi were compared with those reported by EUROCAT. Logistic regression models were adapted to evaluate the association between congenital anomalies and municipality of residence of the mother during pregnancy. RESULTS: Out of 8,503 newborns we recorded 194 subjects with congenital anomalies (228.2/10,000 total births), 1.2 times higher than the one reported by the EUROCAT pool of registries. We observed 83 subjects with congenital heart diseases with an excess of 49.1%. Odds Ratios for congenital heart diseases significantly increased for newborns to mothers resident in Brindisi (OR 1.75 CI 95% 1.30-2.35). CONCLUSIONS: Our findings indicated an increased prevalence of Congenital Anomalies (especially congenital heart diseases) in the city of Brindisi. More research is needed in order to analyze the role of factors potentially involved in the causation of congenital anomalies.

A postural program to reduce dynamic knee valgus during single-limb squatting in young athletes: a preliminary study.

BACKGROUND: Dynamic knee valgus (DKV) is an undesirable multi-joint movement pattern associated with anterior cruciate ligament injury and patellofemoral pain syndrome, especially in sport activities. We assessed DKV in young athletes who followed a postural program to reduce a posterior rigidity mostly attributable to the tightness of hamstring muscles. METHODS: We considered 12- to 18-year-old athletes that followed a six-week program simply based on hamstring stretching and abdominal muscle activation/strengthening. DKV was assessed during a single-limb squat and the frontal plane projection angle (FPPA) between the femur and tibia was considered. RESULTS: Sixty-six athletes with a significant DKV (FPPA≥10°) were identified. Twenty-one subjects exhibited the considered rigidity profile and completed the intervention program. The mean reduction of the FPPA after the intervention was 8.1±7.9°, significantly asymmetric by about 3° (P<0.005) and skewed towards larger negative differences. The average change from the initial condition of -37±25% was statistically significant (P=1.7 x10-6). CONCLUSIONS: This preliminary result suggests that working on enhancing posterior muscle chain flexibility could be effective in reducing DKV in young athletes with a marked tightness of hamstring muscles. Moreover, this simple postural program can be a candidate for inclusion in sport training as a protective strategy against knee injuries.

Laparoscopic sleeve gastrectomy. Do we need to oversew the staple line?

AIM: The aim of this study is to compare the material effectiveness of oversewing the staple line following laparoscopic sleeve gastrectomy. MATERIAL OF STUDY: A prospective randomized trial has been performed on 100 consecutive patients who underwent laparoscopic sleeve gastrectomy. Just before the intervention patients were randomized to receive (Group A) or not receive (Group B) a polypropylene 3-0 running oversewing suture of the staple line. RESULTS: By evaluating preoperative general demographics features and co-morbidities between group A and group B no statistical difference was observed. Main complications evaluated were fistol, bleeding and stenosis and there were no significant difference in fistulas occurrence (p = 0.55) and bleeding (p = 0,65) while on the other hand it has to be remarked how sleeve stenosis has been significantly higher when oversew is performed (p = 0.04). DISCUSSION: Staple line leakage is a worrisome complication of laparoscopic sleeve gastrectomy (LSG). Despite some reports describe oversewing of the staple line as the solution to prevent such problem; other authors have demonstrated the incidence of leaks being the same in oversewed and not oversewed patients. CONCLUSION: This randomized trial has so far shown oversew of LSG to be significantly useless to prevent fistulas formation in patients selected according to our study design.

MiRNA expression profiling in HIV pathogenesis, disease progression and response to treatment: a systematic review.

Aim: A systematic review was conducted to identify the association of miRNA expression with HIV pathogenesis, progression and treatment. Methods: A search of articles was conducted in MEDLINE®, Cochrane Central Register of Controlled Trials and Global Health. Results: 35 articles were included. Due to the heterogeneity of HIV phenotypes, a harmonization based on key progression parameters was proposed. The hsa-miR-29 family, hsa-miR-146b-5p and hsa-miR-150-5p, are the most frequently differentially expressed in HIV. Direct comparison of studies was not possible due to heterogeneity in biological samples and miRNA analysis techniques. Conclusion: This is the first attempt to systematically identify miRNA's different expression in well-defined patient phenotypes and could represent a helpful way to increase general knowledge in this field.

Lay abstract miRNAs play important role in the regulation of gene expression and are involved in various physiological processes. Dysregulation of their function can lead to human diseases including cancer, cardiovascular and metabolic diseases, liver conditions and immune dysfunction. The aim of this work is to systematically analyze the current scientific literature to identify miRNAs linked to the mechanism, development and treatment of HIV. A total of 35 articles were included and the miRNAs that were found with significantly different levels in compared groups of subjects (e.g., subjects with HIV vs healthy persons, persons able to limit the disease progression without therapy vs those whose immune system is already compromised by HIV) were highlighted. The most frequently reported miRNAs were: the hsa-miR-29 family, hsa-miR-146b-5p and hsa-miR-150-5p. To our knowledge, this is the first attempt to systematically identify the miRNAs associated with HIV and could be a useful contribution to general knowledge in this field.

Establishing multiple osteogenic differentiation pathways of mesenchymal stem cells through different scaffold configurations.

Mimicking the complex organization of the extracellular matrix (ECM), especially its structure and dimensionality, is necessary to produce living tissues from stem cells. In compliance with a previously established role of nanofiber organization for the osteogenic differentiation of stem cells, here we used hybrid fibrinogen/poly(l-lactide-ε-caprolactone) (FBG/PLCL) nanofibers arranged in aligned and honeycomb configurations, to recapitulate the highly oriented ECM of the cortical bone and the sponge-like (i.e., honeycomb) environment of the cancellous one, respectively. Using special bilayered constructs, we demonstrate that the dimensionality (i.e., 2D vs. 3D) of the nanofibers as well as their architecture (i.e., honeycomb vs. aligned) affects differently the overall morphology and the expression of multiple osteogenic genes of human adipose-derived mesenchymal stem cells (ADMSCs). The cells had elongated shape with markedly increased cell mobility when seeded on aligned nanofibers. Conversely, on honeycomb-shaped nanofibers, ADMSCs initially concentrated inside the honeycomb curvatures adopting rounded morphology, but late, they formed network-like structures overlaying the honeycomb curvatures. By employing quantitative polymerase chain reaction (qPCR), we further show that a 3D environment generally supports the multiple osteogenic response of ADMSCs, but honeycomb and aligned architectures promote rather different differentiation pathways.

Mechanics of snake biting: Experiments and modelling.

Among all the vertebrates, snakes possess the most sophisticated venom delivering system using their fangs. Fangs of many animals are well adapted to the mechanical loads experienced during the functions such as breaking the diet and puncturing the skin of the prey. Thus, investigation and modelling of puncturing mechanics of snakes is of importance to understand the form-function relationship of the fangs and tissue-fang interactions in detail. We have thus chosen fangs of two snake species, i.e., viper (Bitis arietans) and burrowing snake (Atractaspis aterrima), with different shape and size, and performed insertion experiments using tissue phantoms. Our results showed that the fangs of both species have similar mechanical properties but there was a difference in the insertion forces owing to the difference in shape of the fang. Also, we developed an analytical model of the fang-tissue interaction and obtained a good agreement with the experimental results. Thus, our study can help in the development of bioinspired needles that can potentially have reduced insertion forces and optimised tissue penetration.

Stag Beetle Elytra: Localized Shape Retention and Puncture/Wear Resistance.

Beetles are by far one of the most successful groups of insects, with large diversity in terms of number of species. A part of this success is attributed to their elytra, which provide various functions such as protection to their bodies from mechanical forces. In this study, stag beetle (Lucanus cervus) elytra were first examined for their overall flexural properties and were observed to have a localized shape-retaining snap-through mechanism, which may play a possible role in partly absorbing impact energy, e.g., during battles and falls from heights. The snap-through mechanism was validated using theoretical calculations and also finite element simulations. Elytra were also characterized to examine their puncture and wear resistance. Our results show that elytra have a puncture resistance that is much higher than that of mandible bites. The measured values of modulus and hardness of elytra exocuticle were 10.3 ± 0.8 GPa and 0.7 ± 0.1 GPa, respectively. Using the hardness-to-modulus ratio as an indicator of wear resistance, the estimated value was observed to be in the range of wear-resistant biological material such as blood worms (Glyrcera dibranchiata). Thus, our study demonstrates different mechanical properties of the stag beetle elytra, which can be explored to design shape-retaining bio-inspired composites with enhanced puncture and wear resistance.

Mechanical properties of Chamelea gallina shells at different latitudes.

In this work we evaluate the mechanical properties of Chamelea gallina shells, collected at various locations in the Adriatic Sea, through compression tests. We present an analytical model for the extraction of the material Young's modulus and ultimate strength, based on the approximation of the valves with a simpler geometry. The effect of porosity and the computation of the energy dissipated at fracture are also discussed. Results show a dependence of the mechanical performance on the location at which the samples were collected, i.e. latitude, and thus the environmental factors can affect the rigidity, strength and toughness of the shells. These findings integrate preliminary results published in a previous work.

Obstructive sleep apnoea: Improving healthcare services by combining process modelling and population analysis.

CONTEXT: Disease management broke through in the early 1990s to counterbalance hyper-specialization with a more comprehensive approach. Its role became immediately relevant in chronic conditions and, consequently, in Obstructive Sleep Apnoea (OSA). This is a common chronic condition for which is important to organise services at the local level, taking into account organisational factors and the characteristics of the assisted population. OBJECTIVES: The aim of this work is to propose and apply, coherently with a disease management approach, a combination of healthcare process modelling and population analysis as a way to identify critical issues and explore shared solutions. METHODS: A multidisciplinary working group was created with scholars who are skilled in process analysis, statistics and medicine. Through semi-structured interviews and on-site meetings, healthcare processes were represented with a standard graphical language: Unified Modeling Language™. Population analysis was based on statistical analysis performed on a 5-year retrospective cohort assisted by a Community Pulmonary Service. RESULTS: A shared graphic presentation of the current healthcare process and the results of the statistical analyses constituted the knowledge base to identify critical issues and recommend corresponding solutions, which include: a) refine the local patient database with additional details on comorbidities and risk factors; b) support a greater involvement of "gate-keepers" in the screening phase; c) provide practical tools for the definition of strategies to increment the adherence to therapy; d) include recommendations for physical exercise and interdisciplinary cooperation; and e) define process indicators for measuring the quality of the screening and therapeutic phases. CONCLUSION: The concomitant analyses of formalised processes and critical risk factors represent a useful approach for systematically identifying areas of improvement in healthcare processes and allow us to discuss solutions. Moreover, the specific adoption of UML® for graphical modelling and representation of patient care processes allows us to formalise them by adopting a standard language that can be taken as the basis for implementing web services to support the execution of the modelled processes.

Evidence of friction reduction in laterally graded materials.

In many biological structures, optimized mechanical properties are obtained through complex structural organization involving multiple constituents, functional grading and hierarchical organization. In the case of biological surfaces, the possibility to modify the frictional and adhesive behaviour can also be achieved by exploiting a grading of the material properties. In this paper, we investigate this possibility by considering the frictional sliding of elastic surfaces in the presence of a spatial variation of the Young's modulus and the local friction coefficients. Using finite-element simulations and a two-dimensional spring-block model, we investigate how graded material properties affect the macroscopic frictional behaviour, in particular, static friction values and the transition from static to dynamic friction. The results suggest that the graded material properties can be exploited to reduce static friction with respect to the corresponding non-graded material and to tune it to desired values, opening possibilities for the design of bio-inspired surfaces with tailor-made tribological properties.