Effects of Hyaluronan on Breast Cancer Aggressiveness.

The expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) in breast cancer cells is critical for determining tumor aggressiveness and targeting therapies. The presence of such receptors allows for the use of antagonists that effectively reduce breast cancer growth and dissemination. However, the absence of such receptors in triple-negative breast cancer (TNBC) reduces the possibility of targeted therapy, making these tumors very aggressive with a poor outcome. Cancers are not solely composed of tumor cells, but also include several types of infiltrating cells, such as fibroblasts, macrophages, and other immune cells that have critical functions in regulating cancer cell behaviors. In addition to these cells, the extracellular matrix (ECM) has become an important player in many aspects of breast cancer biology, including cell growth, motility, metabolism, and chemoresistance. Hyaluronan (HA) is a key ECM component that promotes cell proliferation and migration in several malignancies. Notably, HA accumulation in the tumor stroma is a negative prognostic factor in breast cancer. HA metabolism depends on the fine balance between HA synthesis by HA synthases and degradation yielded by hyaluronidases. All the different cell types present in the tumor can release HA in the ECM, and in this review, we will describe the role of HA and HA metabolism in different breast cancer subtypes.

Hyaluronan in the Cancer Cells Microenvironment.

The presence of the glycosaminoglycan hyaluronan in the extracellular matrix of tissues is the result of the cooperative synthesis of several resident cells, that is, macrophages and tumor and stromal cells. Any change in hyaluronan concentration or dimension leads to a modification in stiffness and cellular response through receptors on the plasma membrane. Hyaluronan has an effect on all cancer cell behaviors, such as evasion of apoptosis, limitless replicative potential, sustained angiogenesis, and metastasis. It is noteworthy that hyaluronan metabolism can be dramatically altered by growth factors and matrikines during inflammation, as well as by the metabolic homeostasis of cells. The regulation of HA deposition and its dimensions are pivotal for tumor progression and cancer patient prognosis. Nevertheless, because of all the factors involved, modulating hyaluronan metabolism could be tough. Several commercial drugs have already been described as potential or effective modulators; however, deeper investigations are needed to study their possible side effects. Moreover, other matrix molecules could be identified and targeted as upstream regulators of synthetic or degrading enzymes. Finally, co-cultures of cancer, fibroblasts, and immune cells could reveal potential new targets among secreted factors.

Particle Exclusion Assay: A Tool for Measuring Hyaluronan Pericellular Matrix.

Hyaluronan (HA) is the most abundant glycosaminoglycan in the extracellular matrix, and its deposition is strictly related to changes in cellular behaviors, such as cell migration, proliferation, and adhesion. Pericellular HA is abundant in a variety of cell types, and its amount could reflect specific conditions, thus suggesting a particular cellular status.Particle exclusion assay is a useful tool to visualize pericellular matrices with a high HA content, simply employing microscope image analysis. This approach is quick and allows to visualize the presence of a clear pericellular region around single cells, where fixed red blood cells are excluded if the pericellular matrix has been deposited.

Hyaluronan Regulates Neuronal and Immune Function in the Rat Small Intestine and Colonic Microbiota after Ischemic/Reperfusion Injury.

BACKGROUND: Intestinal ischemia and reperfusion (IRI) injury induces acute and long-lasting damage to the neuromuscular compartment and dysmotility. This study aims to evaluate the pathogenetic role of hyaluronan (HA), a glycosaminoglycan component of the extracellular matrix, as a modulator of the enteric neuronal and immune function and of the colonic microbiota during in vivo IRI in the rat small intestine. METHODS: mesenteric ischemia was induced in anesthetized adult male rats for 60 min, followed by 24 h reperfusion. Injured, sham-operated and non-injured animals were treated with the HA synthesis inhibitor, 4-methylumbelliferone (4-MU 25 mg/kg). Fecal microbiota composition was evaluated by Next Generation Sequencing. Neutrophil infiltration, HA homeostasis and toll like receptor (TLR2 and TLR4) expression in the small intestine were evaluated by immunohistochemical and biomolecular approaches (qRT-PCR and Western blotting). Neuromuscular responses were studied in vitro, in the absence and presence of the selective TLR2/4 inhibitor, Sparstolonin B (SsnB 10, 30 µM). RESULTS: 4-MU significantly reduced IRI-induced enhancement of potentially harmful Escherichia and Enterococcus bacteria. After IRI, HA levels, neutrophil infiltration, and TLR2 and TLR4 expression were significantly enhanced in the muscularis propria, and were significantly reduced to baseline levels by 4-MU. In the injured, but not in the non-injured and sham-operated groups, SsnB reduced both electrical field-stimulated (EFS, 0.1-40 Hz) contractions and EFS-induced (10 Hz) non-cholinergic non-adrenergic relaxations. CONCLUSIONS: enhanced HA levels after intestinal IRI favors harmful bacteria overgrowth, increases neutrophil infiltration and promotes the upregulation of bacterial target receptors, TLR2 and TLR4, in the muscularis propria, inducing a pro-inflammatory state. TLR2 and TLR4 activation may, however, underlay a provisional benefit on excitatory and inhibitory neuronal pathways underlying peristalsis.

Add-On Effect of Selenium and Vitamin D Combined Supplementation in Early Control of Graves' Disease Hyperthyroidism During Methimazole Treatment.

Prompt and stable control of hyperthyroidism is fundamental to avoid the detrimental effects of thyroid hormone excess, and antithyroid drugs, mainly methimazole (MMI), represent the first-line treatment for Graves' disease (GD) hyperthyroidism. Decreased serum concentrations of selenium (Se) and calcifediol (25(OH)D, VitD) have been reported in newly diagnosed GD patients in observational studies. Low Se levels might exacerbate oxidative stress by compromising the antioxidant machinery's response to reactive oxygen species, and low VitD levels might hamper the anti-inflammatory immune response. We performed a randomized controlled clinical trial (EudraCT 2017-00505011) to investigate whether Se and cholecalciferol (VitD) addition to MMI is associated with a prompter control of hyperthyroidism. Forty-two consecutive patients with newly-onset GD and marginal/insufficient Se and VitD levels were randomly assigned to treatment with either MMI monotherapy or MMI combined with Se and VitD. Se treatment was withdrawn after 180 days, while the other treatments were continued. Combination therapy resulted in a significantly greater reduction in serum FT4 concentration at 45 days (-37.9 pg/ml, CI 95%, -43.7 to -32.2 pg/ml) and 180 days (-36.5 pg/ml, CI 95%, -42 to -30.9 pg/ml) compared to MMI monotherapy (respectively: -25.7 pg/ml, CI 95%, -31.6 to -19.7 pg/ml and -22.9 pg/ml, CI 95%, -28 to -17.3 pg/ml, p 0.002). Data at 270 days confirmed this trend (-37.8 pg/ml, CI 95%, -43.6 to -32.1 pg/ml vs -24.4 pg/ml, CI 95%, -30.3 to -18.4 pg/ml). The quality of life (QoL) score was investigated by the validated "Thyroid-related Patient-Reported Outcome" questionnaire (ThyPRO). ThyPRO composite score showed a greater improvement in the intervention group at 45 days (-14.6, CI 95%, -18.8 to -10.4), 180 (-9, CI 95%, -13.9 to -4.2) and 270 days (-14.3, CI 95%, -19.5 to -9.1) compared to MMI group (respectively, -5.2, CI 95%, -9.5 to -1; -5.4, CI 95%, -10.6 to -0.2 and -3.5, CI 95%, -9 to -2.1, p 0-6 months and 6-9 months <0.05). Our results suggest that reaching optimal Se and VitD levels increases the early efficacy of MMI treatment when Se and VitD levels are suboptimal.

The natural antisense transcript HAS2-AS1 regulates breast cancer cells aggressiveness independently from hyaluronan metabolism.

Hyaluronan (HA) is a ubiquitous extracellular matrix component playing a crucial role in the regulation of cell behaviors, including cancer. Aggressive breast cancer cells tend to proliferate, migrate and metastatize. Notably, triple-negative breast cancer cells lacking the expression of estrogen receptor (ER) as well as progesterone receptor and HER2 are more aggressive than ER-positive ones. As currently no targeted therapy is available for triple-negative breast cancer, the identification of novel therapeutic targets has a high clinical priority. In ER-negative cells, tumoral behavior can be reduced by inhibiting HA synthesis or silencing the enzymes involved in its metabolism, such as HA synthase 2 (HAS2). HAS2-AS1 is a long non-coding RNA belonging to the natural antisense transcript family which is known to favor HAS2 gene expression and HA synthesis, thus bolstering malignant progression in brain, ovary, and lung tumors. As the role of HAS2-AS1 has not yet been investigated in breast cancer, in this work we report that ER-positive breast cancers had lower HAS2-AS1 expression compared to ER-negative tumors. Moreover, the survival of patients with ER-negative tumors was higher when the expression of HAS2-AS1 was elevated. Experiments with ER-negative cell lines as MDA-MB-231 and Hs 578T revealed that the overexpression of either the full-length HAS2-AS1 or its exon 2 long or short isoforms alone, strongly reduced cell viability, migration, and invasion, whereas HAS2-AS1 silencing increased cell aggressiveness. Unexpectedly, in these ER-negative cell lines, HAS2-AS1 is involved neither in the regulation of HAS2 nor in HA deposition. Finally, transcriptome analysis revealed that HAS2-AS1 modulation affected several pathways, including apoptosis, proliferation, motility, adhesion, epithelial to mesenchymal transition, and signaling, describing this long non-coding RNA as an important regulator of breast cancer cells aggressiveness.

The role of the multifaceted long non-coding RNAs: A nuclear-cytosolic interplay to regulate hyaluronan metabolism.

In the extracellular matrix (ECM), the glycosaminoglycan (GAG) hyaluronan (HA) has different physiological roles favouring hydration, elasticity and cell survival. Three different isoforms of HA synthases (HAS1, 2, and 3) are responsible for the production of HA. In several pathologies the upregulation of HAS enzymes leads to an abnormal HA accumulation causing cell dedifferentiation, proliferation and migration thus favouring cancer progression, fibrosis and vascular wall thickening. An intriguing new player in HAS2 gene expression regulation and HA production is the long non-coding RNA (lncRNA) hyaluronan synthase 2 antisense 1 (HAS2-AS1). A significant part of mammalian genomes corresponds to genes that transcribe lncRNAs; they can regulate gene expression through several mechanisms, being involved not only in maintaining the normal homeostasis of cells and tissues, but also in the onset and progression of different diseases, as demonstrated by the increasing number of studies published through the last decades. HAS2-AS1 is no exception: it can be localized both in the nucleus and in the cytosol, regulating cancer cells as well as vascular smooth muscle cells behaviour.

HA and HS Changes in Endothelial Inflammatory Activation.

Cardiovascular diseases are a group of disorders caused by the presence of a combination of risk factors, such as tobacco use, unhealthy diet and obesity, physical inactivity, etc., which cause the modification of the composition of the vessel's matrix and lead to the alteration of blood flow, matched with an inflammation condition. Nevertheless, it is not clear if the inflammation is a permissive condition or a consequent one. In order to investigate the effect of inflammation on the onset of vascular disease, we treated endothelial cells with the cytokine TNF-α that is increased in obese patients and is reported to induce cardiometabolic diseases. The inflammation induced a large change in the extracellular matrix, increasing the pericellular hyaluronan and altering the heparan sulfate Syndecans sets, which seems to be related to layer permeability but does not influence cell proliferation or migration nor induce blood cell recruitment or activation.

The Secreted Protein C10orf118 Is a New Regulator of Hyaluronan Synthesis Involved in Tumour-Stroma Cross-Talk.

Interaction between cancer cells and their microenvironment is central in defining the fate of cancer development. Tumour cells secrete signals (cytokines, chemokines, growth factors) that modify the surrounding area, while the niche supplies structures and activities necessary for tumour maintenance and growth. Hyaluronan (HA) is a glycosaminoglycan that constitute cancer cell niche and is known to influence tumour functions such as proliferation, migration and neoangiogenesis. The knowledge of the factors regulating HA synthesis and size is crucial in understanding the mechanisms sustaining tumour development. Here we show that a yet uncharacterized protein secreted by breast tumour cell lines, named c10orf118 (accession number NM_018017 in NCBI/BLAST, and Q7z3E2 according to the Uniprot identifier), with a predicted length of 898 amino acids, can induce the secretion of HA by stromal fibroblasts through the up-regulation of the hyaluronan synthase 2 gene (HAS2). Intracellularly, this protein is localized in the Golgi apparatus with a possible role in vesicle maturation and transport. The expression of c10orf118 was verified in breast cancer patient specimens and was found to be associated with the presence of estrogen receptor that characterizes a good patient survival. We suggest c10orf118 as a new player that influences the HA amount in breast cancer microenvironment and is associated with low aggressiveness of cancer.

Hyaluronan: A Neuroimmune Modulator in the Microbiota-Gut Axis.

The commensal microbiota plays a fundamental role in maintaining host gut homeostasis by controlling several metabolic, neuronal and immune functions. Conversely, changes in the gut microenvironment may alter the saprophytic microbial community and function, hampering the positive relationship with the host. In this bidirectional interplay between the gut microbiota and the host, hyaluronan (HA), an unbranched glycosaminoglycan component of the extracellular matrix, has a multifaceted role. HA is fundamental for bacterial metabolism and influences bacterial adhesiveness to the mucosal layer and diffusion across the epithelial barrier. In the host, HA may be produced and distributed in different cellular components within the gut microenvironment, playing a role in the modulation of immune and neuronal responses. This review covers the more recent studies highlighting the relevance of HA as a putative modulator of the communication between luminal bacteria and the host gut neuro-immune axis both in health and disease conditions, such as inflammatory bowel disease and ischemia/reperfusion injury.

Involvement of hyaluronan in the adaptive changes of the rat small intestine neuromuscular function after ischemia/reperfusion injury.

Intestinal ischemia/reperfusion (I/R) injury has severe consequences on myenteric neurons, which can be irreversibly compromised resulting in slowing of transit and hindered food digestion. Myenteric neurons synthesize hyaluronan (HA) to form a well-structured perineuronal net, which undergoes derangement when myenteric ganglia homeostasis is perturbed, i.e. during inflammation. In this study we evaluated HA involvement in rat small intestine myenteric plexus after in vivo I/R injury induced by clamping a branch of the superior mesenteric artery for 60 min, followed by 24 h of reperfusion. In some experiments, 4-methylumbelliferone (4-MU, 25 mg/kg), a HA synthesis inhibitor, was intraperitoneally administered to normal (CTR), sham-operated (SH) and I/R animals for 24 h. In longitudinal muscle myenteric plexus (LMMP) whole-mount preparations, HA binding protein staining as well as HA levels were significantly higher in the I/R group, and were reduced after 4-MU treatment. HA synthase 1 and 2 (HAS1 and HAS2) labelled myenteric neurons and mRNA levels in LMMPs increased in the I/R group with respect to CTR, and were reduced by 4-MU. The efficiency of the gastrointestinal transit was significantly reduced in I/R and 4-MU-treated I/R groups with respect to CTR and SH groups. In the 4-MU-treated I/R group gastric emptying was reduced with respect to the CTR, SH and I/R groups. Carbachol (CCh) and electrical field (EFS, 0.1-40 Hz) stimulated contractions and EFS-induced (10 Hz) NANC relaxations were reduced in the I/R group with respect to both CTR and SH groups. After I/R, 4-MU treatment increased EFS contractions towards control values, but did not affect CCh-induced contractions. NANC on-relaxations after I/R were not influenced by 4-MU treatment. Main alterations in the neurochemical coding of both excitatory (tachykinergic) and inhibitory pathways (iNOS, VIPergic) were also observed after I/R, and were influenced by 4-MU administration. Overall, our data suggest that, after an intestinal I/R damage, changes of HA homeostasis in specific myenteric neuron populations may influence the efficiency of the gastrointestinal transit. We cannot exclude that modulation of HA synthesis in these conditions may ameliorate derangement of the enteric motor function preventing, at least in part, the development of dysmotility.

Heparan Sulfate in the Tumor Microenvironment.

The biology of tumor cells strictly depends on their microenvironment architecture and composition, which controls the availability of growth factors and signaling molecules. Thus, the network of glycosaminoglycans, proteoglycans, and proteins known as extracellular matrix (ECM) that surrounds the cells plays a central role in the regulation of tumor fate. Heparan sulfate (HS) and heparan sulfate proteoglycans (HSPGs) are highly versatile ECM components that bind and regulate the activity of growth factors, cell membrane receptors, and other ECM molecules. These HS binding partners modulate cell adhesion, motility, and proliferation that are processes altered during tumor progression. Modification in the expression and activity of HS, HSPGs, and the respective metabolic enzymes results unavoidably in alteration of tumor cell microenvironment. In this light, the targeting of HS structure and metabolism is potentially a new tool in the treatment of different cancer types.

Sirtuin 1 reduces hyaluronan synthase 2 expression by inhibiting nuclear translocation of NF-κB and expression of the long-noncoding RNA HAS2-AS1.

Hyaluronan (HA) is one of the most prevalent glycosaminoglycans of the vascular extracellular matrix (ECM). Abnormal HA accumulation within blood vessel walls is associated with tissue inflammation and is prominent in most vascular pathological conditions such as atherosclerosis and restenosis. Hyaluronan synthase 2 (HAS2) is the main hyaluronan synthase enzyme involved in HA synthesis and uses cytosolic UDP-glucuronic acid and UDP-GlcNAc as substrates. The synthesis of UDP-glucuronic acid can alter the NAD+/NADH ratio via the enzyme UDP-glucose dehydrogenase, which oxidizes the alcohol group at C6 to the COO- group. Here, we show that HAS2 expression can be modulated by sirtuin 1 (SIRT1), the master metabolic sensor of the cell, belonging to the class of NAD+-dependent deacetylases. Our results revealed the following. 1) Treatments of human aortic smooth muscle cells (AoSMCs) with SIRT1 activators (SRT1720 and resveratrol) inhibit both HAS2 expression and accumulation of pericellular HA coats. 2) Tumor necrosis factor α (TNFα) induced HA-mediated monocyte adhesion and AoSMC migration, whereas SIRT1 activation prevented immune cell recruitment and cell motility by reducing the expression levels of the receptor for HA-mediated motility, RHAMM, and the HA-binding protein TNF-stimulated gene 6 protein (TSG6). 3) SIRT1 activation prevented nuclear translocation of NF-κB (p65), which, in turn, reduced the levels of HAS2-AS1, a long-noncoding RNA that epigenetically controls HAS2 mRNA expression. In conclusion, we demonstrate that both HAS2 expression and HA accumulation by AoSMCs are down-regulated by the metabolic sensor SIRT1.

Revisiting the hallmarks of cancer: The role of hyaluronan.

Extracellular matrix (ECM) is a complex network of macromolecules such as proteoglycans (PGs), glycosaminoglycans (GAGs) and fibrous proteins present within all tissues and organs. The main role of ECM is not only to provide an essential mechanical scaffold for the cells but also to mediate crucial biochemical cues that are required for tissue homeostasis. Dysregulations in ECM deposition alter cell microenvironment, triggering the onset or the rapid progression of several diseases, including cancer. Hyaluronan (HA) is a ubiquitous component of ECM considered as one of the main players of cancer initiation and progression. This review discusses how HA participate in and regulate several aspects of tumorigenesis, with particular attention to the hallmarks of cancer proposed by Hanahan and Weinberg such as sustaining of the proliferative signaling, evasion of apoptosis, angiogenesis, activation of invasion and metastases, reprogramming of energy metabolism and evasion of immune response.

Method for Studying ECM Expression: In Situ RT-PCR.

The gene expression of the extracellular matrix macromolecules is critical in the analysis of various pathologies. The use of a RT-PCR directly on a fixed tissue enables the recognition of the real expressing cells for any ECM molecules together with the tissue localization. The method here described is easy to perform using the same material as for common immunostaining and the same primers used for quantitative RT-PCR. Moreover, the used primers, designed with a final amplicon that spans the exon-exon junction, allow to detect the cDNA but not the gDNA sequences.

Method for Detecting Hyaluronan in Isolated Myenteric Plexus Ganglia of Adult Rat Small Intestine.

The cellular components of the enteric nervous system (ENS), namely enteric neurons and glia, display plasticity and respond to environmental cues deriving from growth factors, extracellular matrix (ECM) molecules, and cell-surface molecules, both in physiological and pathological conditions. ECM, in particular, provides an important framework for the enteric microenvironment and influences the homeostasis of myenteric neuronal circuitries. Isolation of pure myenteric plexus preparations from adult tissue permits to investigate changes in the ENS involving specific ECM, such as hyaluronan. This approach is based upon the possibility to isolate myenteric ganglia from the intestinal wall of either adult animals or humans, after microdissection and subsequent enzymatic digestion of the tissue. Enteric ganglia are free of connective tissue, extracellular collagen, and blood vessels, and thus treatment of intact intestinal segments with highly purified collagenases permits ganglia isolation from the surrounding smooth muscle cells. In this chapter, we describe methods for visualizing HA in isolated primary cultures of adult rat small intestine myenteric ganglia.

Changes in hyaluronan deposition in the rat myenteric plexus after experimentally-induced colitis.

Myenteric plexus alterations hamper gastrointestinal motor function during intestinal inflammation. Hyaluronan (HA), an extracellular matrix glycosaminoglycan involved in inflammatory responses, may play a role in this process. In the colon of control rats, HA-binding protein (HABP), was detected in myenteric neuron soma, perineuronal space and ganglia surfaces. Prominent hyaluronan synthase 2 (HAS2) staining was found in myenteric neuron cytoplasm, suggesting that myenteric neurons produce HA. In the myenteric plexus of rats with 2, 4-dinitrobenzene sulfonic (DNBS)-induced colitis HABP staining was altered in the perineuronal space, while both HABP staining and HA levels increased in the muscularis propria. HAS2 immunopositive myenteric neurons and HAS2 mRNA and protein levels also increased. Overall, these observations suggest that inflammation alters HA distribution and levels in the gut neuromuscular compartment. Such changes may contribute to alterations in the myenteric plexus.

In vitro effects of Apixaban on 5 different cancer cell lines.

BACKGROUND: Cancer is associated with hypercoagulability. However, several data suggest that anticoagulant drugs may have an effect on tumor development and progression mediated by both coagulation dependent processes and non-coagulation dependent processes. Therefore, we investigated the in vitro effects of Apixaban on cell proliferation, mortality, cell migration, gene expression and matrix metalloproteinase in 5 different cancer cell lines. METHODS: The following cancer cell lines, and 2 normal fibroblast cultures (lung and dermal fibroblasts), were studied: OVCAR3 (ovarian cancer), MDA MB 231 (breast cancer), CaCO-2 (colon cancer), LNCaP (prostate cancer) and U937 (histiocytic lymphoma). Proliferation and cell mortality were assessed in control cells and Apixaban treated cultures (dose from 0.1 to 5 µg/ml, 0 to 96-h). Necrosis/Apoptosis (fluorescence microscopy), cell migration (24-h after scratch test), matrix metalloproteinase (MMP) activity and mRNA expression (RT PCR) of p16, p21, p53 and HAS were also assessed. RESULTS: High-dose (5 µg/ml) Apixaban incubation was associated with a significantly reduced proliferation in 3 cancer cell lines (OVCAR3, CaCO-2 and LNCaP) and with increased cancer cell mortality in all, except LNCaP, cancer lines. Apoptosis seems to account for the increased mortality. The migration capacity seems to be impaired after high-dose Apixaban incubation in OVCAR3 and CaCO-2 cells. Data on mRNA expression suggest a consistent increase in tumor suppression gene p16 in all cell lines. CONCLUSIONS: Our data suggest that high-dose Apixaban may be able to interfere with cancer cell in vitro, reducing proliferation and increasing cancer cell mortality through apoptosis in several cancer cell lines.

Extracellular Matrix in Atherosclerosis: Hyaluronan and Proteoglycans Insights.

BACKGROUND: Atherosclerosis, a chronic inflammatory disease of the blood vessel wall, is the most common cause of cardiovascular pathologies. Hyaluronan, the major polysaccharide involved in this process, plays a pivotal role acting as a modulator of all inflammatory stages, affecting the behavior of both endothelial and smooth muscle cells. OBJECTIVE: The inflammatory condition is the main reason of the increased deposition of extracellular matrix, that in turn, traps lipoproteins and inflammatory/growth factors from the circulation within the vessel wall and thicken the arterial wall. Therefore, this chronic condition that continuously affects the arterial walls in a specific area causes a severe remodeling of the tissue architecture and a drastic change in the resident cell behavior. METHODS: Because of the great complexity of the extracellular matrix in the arterial wall, we investigate the modification in the different layers of the vessels with a particular attention to hyaluronan and proteoglycans and to the events that affects their normal turnover. RESULTS: Hyaluronan, the major polysaccharide involved in this process, plays a pivotal role acting as a modulator of all inflammatory stages, affecting the behavior of both endothelial and smooth muscle cells. Moreover, glycosaminoglycans and proteoglycans had been shown to change during the lesion progression, and to possess the chemical features essential for lipid retention, immune system activation, smooth cells proliferation and macrophages recruitment. CONCLUSION: The ECM characteristics should be investigated in order to understand their prevention potentials as well as their negative impact on the onset of the disease.

Biology and biotechnology of hyaluronan.

The hyaluronan (HA) polymer is a critical component of extracellular matrix with a remarkable structure: is a linear and unbranched polymer without sulphate or phosphate groups. It is ubiquitous in mammals showing several biological functions, ranging from cell proliferation and migration to angiogenesis and inflammation. For its critical biological functions the amount of HA in tissues is carefully controlled by different mechanisms including covalent modification of the synthetic enzymes and epigenetic control of their gene expression. The concentration of HA is also critical in several pathologies including cancer, diabetes and inflammation. Beside these biological roles, the structural properties of HA allow it to take advantage of its capacity to form gels even at concentration of 1 % producing scaffolds with very promising applications in regenerative medicine as biocompatible material for advanced therapeutic uses. In this review we highlight the biological aspects of HA addressing the mechanisms controlling the HA content in tissues as well as its role in important human pathologies. In the second part of the review we highlight the different use of HA polymers in the modern biotechnology.