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1.
Clin Nutr ; 43(6): 1433-1446, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38704983

ABSTRACT

The prevalence of childhood and adolescent obesity has globally reached alarming dimensions and many adolescents affected by obesity already present one or more obesity-related comorbidities. In recent years, emerging evidence supporting the role of gut microbiota in the pathophysiology of metabolic diseases has been reported and the use of prebiotics, probiotics, synbiotics and postbiotics as a strategy to manipulate gut microbiota has become popular. The aim of this review is to explore the relationship between gut microbiota and metabolic syndrome in adolescents and to discuss the potential use of prebiotics, probiotics, synbiotics and postbiotics for the prevention and treatment of this clinical picture in adolescence. According to the most recent literature, prebiotics, probiotics and synbiotics have no clear effect on MetS, but a possible modulation of anthropometric parameters has been observed after synbiotic supplementation. Only one study has examined the role of postbiotics in alleviating metabolic complications in children with obesity but not in adolescents. More extensive research is needed to support the conclusions drawn so far and to develop effective microbiome-based interventions that may help improving the quality of life of children and adolescents exposed to the increasing prevalence of MetS.


Subject(s)
Gastrointestinal Microbiome , Metabolic Syndrome , Pediatric Obesity , Prebiotics , Probiotics , Synbiotics , Humans , Metabolic Syndrome/therapy , Metabolic Syndrome/microbiology , Prebiotics/administration & dosage , Probiotics/administration & dosage , Probiotics/therapeutic use , Synbiotics/administration & dosage , Adolescent , Pediatric Obesity/therapy , Pediatric Obesity/microbiology , Child
2.
Biomedicines ; 12(1)2024 Jan 19.
Article in English | MEDLINE | ID: mdl-38275405

ABSTRACT

Endocrine disruptors (EDCs) are chemicals that interfere with the endocrine system. EDC exposure may contribute to the development of obesity, type 2 diabetes, and cardiovascular diseases by impacting the composition of an infant's gut microbiota during the first 1000 days of life. To explore the relationship between maternal urinary levels of Bisphenol-A and phthalates (UHPLC-MS/MS), and the composition of the infant gut microbiota (16S rDNA) at age 12 months (T3) and, retrospectively, at birth (T0), 1 month (T1), and 6 months (T2), stool samples from 20 infants breastfed at least once a day were analyzed. Metataxonomic bacteria relative abundances were correlated with EDC values. Based on median Bisphenol-A levels, infants were assigned to the over-exposed group (O, n = 8) and the low-exposed group (B, n = 12). The B-group exhibited higher gut colonization of the Ruminococcus torques group genus and the O-group showed higher abundances of Erysipelatoclostridium and Bifidobacterium breve. Additionally, infants were stratified as high-risk (HR, n = 12) or low-risk (LR, n = 8) exposure to phthalates, based on the presence of at least three phthalates with concentrations exceeding the cohort median values; no differences were observed in gut microbiota composition. A retrospective analysis of gut microbiota (T0-T2) revealed a disparity in ß-diversity between the O-group and the B-group. Considering T0-T3, the Linear Discriminant Effect Size indicated differences in certain microbes between the O-group vs. the B-group and the HR-group vs. the LR-group. Our findings support the potential role of microbial communities as biomarkers for high EDC exposure levels. Nevertheless, further investigations are required to deeply investigate this issue.

3.
Geroscience ; 46(2): 2123-2137, 2024 Apr.
Article in English | MEDLINE | ID: mdl-37857994

ABSTRACT

Insulin resistance (IR) and cardiovascular diseases (CVD) are relevant concerns in the elderly population; as the world's population ages, IR and CVD are two universal public health problems. While a link between IR a CVD has been established, the mediating mechanisms are uncertain and rigorous investigations are needed to fully elucidate them. The study aimed at assessing the relationship between epicardial fat (EF), an indicator of cardiovascular risk, and IR in Italian free-living elderly (n = 89). Baseline data from a previous cohort was used. Anthropometric measurements, EF, and IR-related variables, including the HOMA-IR index and other biochemical parameters were obtained. The correlation between EF and IR was explored. Further analysis was conducted to identify significant differences regarding IR variables among EF quartiles. EF correlated positively with glucose levels in females, males and the total population. The pairwise comparison among EF quartiles showed significant differences in glucose levels, HOMA-IR index, triglycerides, and total cholesterol levels. To our knowledge, this is the only study assessing the relationship between EF and IR in healthy elderly, while most of the studies have investigated EF and IR in diseased populations. Further research with a longitudinal approach should be conducted to design concrete conclusions about this relationship.


Subject(s)
Cardiovascular Diseases , Insulin Resistance , Male , Female , Humans , Aged , Cross-Sectional Studies , Epicardial Adipose Tissue , Cardiovascular Diseases/epidemiology , Glucose
4.
Nutrients ; 15(3)2023 Jan 30.
Article in English | MEDLINE | ID: mdl-36771409

ABSTRACT

Sugar-sweetened beverages (SSBs) are major contributors of free sugars to the diet. A strong relationship between SSB intake and weight gain is described. METHODS: we performed a narrative review to present an overview of the role of SSBs as a pivotal contributor in the development of obesity and metabolism-related complications. RESULTS: different factors influence SSB consumption in children, including economic variables, individual attributes and behaviors to environmental factors, parent features and parents' behaviors. Data suggest that SSB intake has a negative effect on weight and obesity-related diseases. The leading mechanism linking SSB intake to the risk of gaining weight is decreased satiety and incomplete compensatory reduction in energy intake at meals following ingestion of liquid calories. Additionally, the effects of SSBs on gut microbiota and on eating behaviors were also reported. An association between SSB intake, weight gain and cardiometabolic risks is evident. Consumption of SSBs had a significant impact on the prevalence of obesity and related metabolic risks, including insulin resistance, type 2 diabetes, hypertension and metabolic syndrome. CONCLUSIONS: Limiting consumption of SSBs and increasing knowledge of the effect of SSBs on early metabolic and cardiovascular disorders will be useful in developing strategies to counteract the problem and to prevent obesity and related complications.Key future research areas for which further studies are needed include investigating the long-term effects of SSBs on health outcomes as well as analyzing the health effects of sugar consumed in solid compared to liquid forms and further elucidating the biological mechanisms of sugar addiction and energy compensation.


Subject(s)
Diabetes Mellitus, Type 2 , Pediatric Obesity , Sugar-Sweetened Beverages , Adolescent , Humans , Child , Sugar-Sweetened Beverages/adverse effects , Diabetes Mellitus, Type 2/epidemiology , Diabetes Mellitus, Type 2/etiology , Pediatric Obesity/etiology , Pediatric Obesity/complications , Beverages/adverse effects , Weight Gain , Sugars
5.
Dev Cell ; 58(3): 174-191.e8, 2023 02 06.
Article in English | MEDLINE | ID: mdl-36706755

ABSTRACT

The blood barriers of the nervous system protect neural environments but can hinder therapeutic accessibility. The blood-brain barrier (BBB) is well characterized, consisting of endothelial cells with specialized tight junctions and low levels of transcytosis, properties conferred by contacting pericytes and astrocytes. In contrast, the blood-nerve barrier (BNB) of the peripheral nervous system is poorly defined. Here, we characterize the structure of the mammalian BNB, identify the processes that confer barrier function, and demonstrate how the barrier can be opened in response to injury. The homeostatic BNB is leakier than the BBB, which we show is due to higher levels of transcytosis. However, the barrier is reinforced by macrophages that specifically engulf leaked materials, identifying a role for resident macrophages as an important component of the BNB. Finally, we demonstrate the exploitation of these processes to effectively deliver RNA-targeting therapeutics to peripheral nerves, indicating new treatment approaches for nervous system pathologies.


Subject(s)
Blood-Nerve Barrier , Endothelial Cells , Animals , Blood-Nerve Barrier/physiology , Endothelial Cells/physiology , Blood-Brain Barrier/physiology , Macrophages , Pericytes/physiology , Mammals
6.
Article in English | MEDLINE | ID: mdl-35886152

ABSTRACT

Obesity in childhood and adolescence represents a serious health problem worldwide. Similarly, eating disorders (EDs) are complex diseases that affect adolescents with an increasing prevalence and are an alarming health concern to both physical and mental health. Traditionally, obesity and EDs, particularly binge eating disorder (BED), have been considered separate conditions, but there is emerging evidence such as etiology, comorbidities, risk factors, psychosocial impairment, and prevention approaches, highlighting important overlaps among these conditions. In youth, the two conditions share risk factors and consequences at both the physical and psychological levels, requiring special care. Exercise, useful as strategy to prevent and treat overweight conditions, may have beneficial effects on BED symptoms, suggesting that it may be considered as one of the key factors in the treatment of individuals affected by obesity with BED. The purpose of this narrative review is to examine the bidirectional impact of obesity and BED in adolescents, in terms of risk factors, etiology and comorbid conditions. Specifically, we focused on the benefits of physical activity (PA) in the multidisciplinary treatment of subjects affected by obesity with BED. Even though additional research is needed to reach conclusions about the role of exercise in the treatment of obesity and comorbid BED, especially in adolescents, promising results have already suggested that closely monitored exercise is safe and, paired with cognitive behavioral therapy, may provide multiple benefits on both the physical and psychological levels. Tailored and integrated treatments for weight management and eating disorders are important to promptly and effectively treat obese subjects that have BED.


Subject(s)
Binge-Eating Disorder , Cognitive Behavioral Therapy , Pediatric Obesity , Adolescent , Binge-Eating Disorder/epidemiology , Binge-Eating Disorder/psychology , Binge-Eating Disorder/therapy , Exercise , Humans , Overweight/psychology , Pediatric Obesity/psychology , Pediatric Obesity/therapy
7.
Nutr Res Rev ; 35(1): 98-111, 2022 06.
Article in English | MEDLINE | ID: mdl-33926597

ABSTRACT

BACKGROUND: Sarcopenia (SA) is a progressive skeletal muscle disorder, associated with increased risk of adverse outcomes, including falls, fractures, physical disability and mortality. Several risks factors may contribute to the development of SA in the elderly; among them, nutrition plays a key role in muscle health. The elderly are at risk of inadequate intake in terms of micronutrients affecting muscle homeostasis, such as B vitamins, related to homocysteine (Hcy) metabolism. OBJECTIVES AND METHODS: This narrative review analysed the association between increased Hcy levels and SA, according to the criteria of the International Working Group on Sarcopenia, the European Working Group on Sarcopenia in Older People and the Asian Working Group for Sarcopenia. The authors focused not only on SA per se but also on exploring the association between increased Hcy levels and components of SA, including muscle mass, muscle strength and physical performance. RESULTS: Results are inconsistent, except for muscle mass, showing no significant associations with Hcy levels. CONCLUSIONS: Few and conflicting data emerged in this review on the association between SA and increased Hcy levels due to numerous differences between studies that change the significance of the association of Hcy and SA, as well as the muscle strength, muscle mass and physical performance. Furthermore, because the ageing process is not uniform in the population owing to differences in genetics, lifestyle and general health, chronological age fails to address the observed heterogeneity among the 'elderly' of the studies reported in this revision. Therefore, further studies are still needed.


Subject(s)
Sarcopenia , Aged , Homocysteine , Humans , Muscle Strength/physiology , Muscle, Skeletal/pathology , Physical Functional Performance , Sarcopenia/etiology
8.
Article in English | MEDLINE | ID: mdl-34574636

ABSTRACT

Background: Endocrine-disrupting chemicals (EDCs) are compounds that interfere with aspects of hormonal signaling. Considerable attention has been paid to their biological effects especially in women of childbearing age or during pregnancy as EDCs have been reported to cross the placenta becoming concentrated in the fetus' circulation. Lifestyle habits, daily consumption of packaged foods and use of healthcare/cosmetic products are associated with increased EDCs levels. This cross-sectional research examined the EDCs levels and the lifestyle determinants of EDC exposure in a cohort of reproductive-age women from Northern Italy. Methods: Forty-five women (median age: 36, IQR: 30-38) were evaluated for urinary bisphenol A (BPA) and phthalates levels and also studied for EDCs' major determinants of daily exposure; food frequency/dietary, physical activity, smoking habits and weight status. Results: Although 100% of women seemed to have been exposed to common sources of EDCs, they reported a healthy lifestyle. The multivariable model described a positive and significant association between consumption of sauces/dressings in plastic containers and monoethyl phthalate exposure (p = 0.037). Conclusions: Since reproductive age encompasses a critical window for future health and functioning of the "mothers-to-be" and their children, future studies on prenatal dietary BPA and phthalate exposure and the role of consumer product choices in reducing such exposure are recommended.


Subject(s)
Endocrine Disruptors , Environmental Pollutants , Phthalic Acids , Adult , Benzhydryl Compounds/analysis , Benzhydryl Compounds/toxicity , Cross-Sectional Studies , Endocrine Disruptors/toxicity , Environmental Exposure , Environmental Pollutants/toxicity , Female , Habits , Humans , Life Style , Phenols , Phthalic Acids/toxicity , Pilot Projects , Pregnancy
9.
Cancers (Basel) ; 12(9)2020 Sep 21.
Article in English | MEDLINE | ID: mdl-32967380

ABSTRACT

A mesoporous silica-based nanodevice bearing the antineoplastic drug bortezomib (BTZ), whose release is triggered in acidic environment and grafted with folic acid (FOL) as a targeting function (FOL-MSN-BTZ) was tested on folate receptor overexpressing (FR+) multiple myeloma (MM) cells and on FR negative (FR-) normal cells. FOL-MSN-BTZ efficacy studies were conducted by means of growth experiments, TEM, TUNEL assay and Western Blotting analysis (WB). Metabolic investigations were performed to assess cells metabolic response to MSNs treatments. FOL-MSN-BTZ exclusively killed FR+ MM cells, leading to an apoptotic rate that was comparable to that induced by free BTZ, and the effect was accompanied by metabolic dysfunction and oxidative stress. Importantly, FOL-MSN-BTZ treated FR- normal cells did not show any significant sign of injury or metabolic perturbation, while free BTZ was still highly toxic. Notably, the vehicle alone (MSN-FOL) did not affect any biological process in both tested cell models. These data show the striking specificity of FOL-MSN-BTZ toward FR+ tumor cells and the outstanding safety of the MSN-FOL vehicle, paving the way for a future exploitation of FOL-MSN-BTZ in MM target therapy.

10.
Nutr Res Rev ; 32(2): 169-175, 2019 12.
Article in English | MEDLINE | ID: mdl-30947761

ABSTRACT

The WHO reported that high blood pressure (BP) is one of the primary causes of death worldwide. Hypertension (HPT) is a major risk factor for CVD and related diseases as well as for diseases, leading to a considerable increase in cardiovascular risk. Since BP response could also be influenced by caffeine, which is widely consumed with coffee and other items, it is important to define the possible effects associated with caffeine intake. The most recent findings aimed at clarifying the role of caffeine consumption on BP and HPT risk/incidence are conflicting and difficult to interpret. Therefore, in the present narrative review, we aimed to examine various methodological inaccuracies/aspects and factors that make studies difficult to be compared, in order to obtain a single consensus on the effects of caffeine intake on the risk of BP and HPT. We observed that this heterogeneity in results could be due to the presence of: (i) several variables affecting BP (such as age, sex, genetic and lifestyle aspects); (ii) different caffeine content of food and beverages; and (iii) caffeine metabolism. Moreover, different methodological aspects in the evaluation of daily dietary caffeine intake and in the BP measurement could add some other bias in the interpretation of results. Therefore, it is mandatory to consider all methodological aspects and confounding factors to generate a standardised methodology in order to increase cross-study consistency and minimise confounding effects of different variables on the relationship between BP response and HPT risk/incidence after caffeine intake.


Subject(s)
Blood Pressure/drug effects , Caffeine/adverse effects , Hypertension/epidemiology , Adolescent , Adult , Aged , Blood Pressure/genetics , Cacao , Caffeine/administration & dosage , Coffee , Cohort Studies , Cytochrome P-450 CYP1A2/genetics , Drugs, Chinese Herbal , Eleutherococcus , Female , Humans , Hypertension/genetics , Life Style , Male , Middle Aged , Polymorphism, Genetic , Randomized Controlled Trials as Topic , Risk Factors , Sex Factors
11.
Front Pediatr ; 7: 123, 2019.
Article in English | MEDLINE | ID: mdl-31024868

ABSTRACT

The prevalence of obesity in children/adolescents has increased worldwide during the past 30 years, becoming a significant public health concern; prevention, and management of pediatric obesity onset is one of the most critical public health goals for both industrialized and developing countries. Pediatric obesity has been identified as a risk factor for various psychopathologies, including eating disorders (ED). Although it has been demonstrated that a comprehensive multidisciplinary treatment (MT), with small steps and practical approaches to lifestyle change, can be an effective treatment for children and adolescents with obesity, to the best of our knowledge, this is the first systematic review investigating the effect of MT on the development, progression or decrease of ED symptoms (EDS) in this target population. PubMed and Web of Science databases were searched (last search on 18 February 2019) according to a predetermined search strategy, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guidelines and Statement. Original studies published in English examining the effect of MT on pediatric overweight/obesity, paying particularly attention at the development of EDS, were eligible for inclusion. Seven hundred and forty-four records have been identified; nine articles with study quality ranging from weak to moderate have been included. MTs were heterogeneous in nature including length, number, frequency and type of sessions, parent-involvement and use of technology, besides several psychometric questionnaires were used to screen for EDS, since there are no standardized criteria. In 3 studies there was a significant decrease in external and emotional eating and in four studies a significant increase in restraint eating post MT. Two studies found a significant decrease of binge eating symptoms and other two studies showed an improvement of self-perception, weight, and shape concern. A statistical significant decrease in BMI, BMIz, BMISDS, and adjusted BMI was observed after all MTs, except one. A narrative summary of the evidences reported highlighted the positive impact of MT on the EDS. Moreover, since weight loss post MTs was not necessarily related to EDS, clinicians should also look for the presence of EDS and treat them accordingly.

12.
Nanoscale Adv ; 1(8): 3269-3278, 2019 Aug 06.
Article in English | MEDLINE | ID: mdl-36133588

ABSTRACT

A mesoporous silica-based drug delivery device potentially useful for bone-specific drug delivery has been designed, developed and characterized starting from MSU-type mesoporous silica. The proposed system consists of a mesoporous silica nanoparticles (MSN) based vehicle, presenting alendronate as a targeting functionality for bone tissue while ibuprofen is used as a model molecule for the drugs to be delivered. The particles are functionalized on the external surface using a propionitrile derivative that is successively hydrolyzed to a carboxylic group. Alendronate, one of the most used member of the diphosphonate drug class, is electrostatically bonded to the external carboxyl functionalities of mesoporous silica. The obtained material has been characterized by powder X-ray diffraction, N2 adsorption-desorption porosimetry, UV-vis spectrophotometry, FT-IR spectrometry and MAS-NMR 13C and 29Si. Hydroxyapatite, which simulates the bone matrix, has been synthesized with the aim of testing the targeting activity of the obtained device. In a separate test, the MSNs have been loaded with ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), and its release has been determined under neutral conditions by HPLC. Moreover, biological tests were carried out. The tested devices did not show any toxicity towards normal cells, confirming their high biocompatibility and the lack of off-target effects.

13.
Cell Rep ; 25(10): 2755-2765.e5, 2018 12 04.
Article in English | MEDLINE | ID: mdl-30517863

ABSTRACT

The formation of myelinating Schwann cells (mSCs) involves the remarkable biogenic process, which rapidly generates the myelin sheath. Once formed, the mSC transitions to a stable homeostatic state, with loss of this stability associated with neuropathies. The histone deacetylases histone deacetylase 1 (HDAC1) and HDAC2 are required for the myelination transcriptional program. Here, we show a distinct role for HDAC3, in that, while dispensable for the formation of mSCs, it is essential for the stability of the myelin sheath once formed-with loss resulting in progressive severe neuropathy in adulthood. This is associated with the prior failure to downregulate the biogenic program upon entering the homeostatic state leading to hypertrophy and hypermyelination of the mSCs, progressing to the development of severe myelination defects. Our results highlight distinct roles of HDAC1/2 and HDAC3 in controlling the differentiation and homeostatic states of a cell with broad implications for the understanding of this important cell-state transition.


Subject(s)
Histone Deacetylases/metabolism , Homeostasis , Myelin Sheath/metabolism , Schwann Cells/cytology , Schwann Cells/enzymology , Aging/metabolism , Animals , Mice, Inbred C57BL , Myelin Sheath/ultrastructure , Rats , Sciatic Nerve/metabolism , Sciatic Nerve/ultrastructure , Transcription, Genetic
14.
Development ; 145(24)2018 12 14.
Article in English | MEDLINE | ID: mdl-30413560

ABSTRACT

Peripheral nerves are highly regenerative, in contrast to the poor regenerative capabilities of the central nervous system (CNS). Here, we show that adult peripheral nerve is a more quiescent tissue than the CNS, yet all cell types within a peripheral nerve proliferate efficiently following injury. Moreover, whereas oligodendrocytes are produced throughout life from a precursor pool, we find that the corresponding cell of the peripheral nervous system, the myelinating Schwann cell (mSC), does not turn over in the adult. However, following injury, all mSCs can dedifferentiate to the proliferating progenitor-like Schwann cells (SCs) that orchestrate the regenerative response. Lineage analysis shows that these newly migratory, progenitor-like cells redifferentiate to form new tissue at the injury site and maintain their lineage, but can switch to become a non-myelinating SC. In contrast, increased plasticity is observed during tumourigenesis. These findings show that peripheral nerves have a distinct mechanism for maintaining homeostasis and can regenerate without the need for an additional stem cell population.This article has an associated 'The people behind the papers' interview.


Subject(s)
Central Nervous System/physiology , Homeostasis , Nerve Regeneration/physiology , Neural Stem Cells/cytology , Peripheral Nerves/physiology , Animals , Axons/metabolism , Carcinogenesis/pathology , Cell Proliferation , Extracellular Matrix Proteins/metabolism , Mice, Inbred C57BL , Mice, Transgenic , Myelin Sheath/metabolism , Neural Stem Cells/metabolism , Neuronal Plasticity , Peripheral Nerves/cytology , Peripheral Nerves/ultrastructure , Schwann Cells/metabolism
15.
Cell ; 162(5): 1127-39, 2015 Aug 27.
Article in English | MEDLINE | ID: mdl-26279190

ABSTRACT

The peripheral nervous system has remarkable regenerative capacities in that it can repair a fully cut nerve. This requires Schwann cells to migrate collectively to guide regrowing axons across a 'bridge' of new tissue, which forms to reconnect a severed nerve. Here we show that blood vessels direct the migrating cords of Schwann cells. This multicellular process is initiated by hypoxia, selectively sensed by macrophages within the bridge, which via VEGF-A secretion induce a polarized vasculature that relieves the hypoxia. Schwann cells then use the blood vessels as "tracks" to cross the bridge taking regrowing axons with them. Importantly, disrupting the organization of the newly formed blood vessels in vivo, either by inhibiting the angiogenic signal or by re-orienting them, compromises Schwann cell directionality resulting in defective nerve repair. This study provides important insights into how the choreography of multiple cell-types is required for the regeneration of an adult tissue.


Subject(s)
Blood Vessels/metabolism , Macrophages/metabolism , Peripheral Nerves/physiology , Schwann Cells/metabolism , Animals , Axons/metabolism , Cell Hypoxia , Endothelial Cells/metabolism , Inflammation/metabolism , Male , Mice , Neovascularization, Physiologic , Rats , Rats, Sprague-Dawley , Regeneration , Vascular Endothelial Growth Factor A/genetics
16.
Acta Biomater ; 14: 22-32, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25527093

ABSTRACT

The need for improved renal replacement therapies has stimulated innovative research for the development of a cell-based renal assist device. A key requirement for such a device is the formation of a "living membrane", consisting of a tight kidney cell monolayer with preserved functional organic ion transporters on a suitable artificial membrane surface. In this work, we applied a unique conditionally immortalized proximal tubule epithelial cell (ciPTEC) line with an optimized coating strategy on polyethersulfone (PES) membranes to develop a living membrane with a functional proximal tubule epithelial cell layer. PES membranes were coated with combinations of 3,4-dihydroxy-l-phenylalanine and human collagen IV (Coll IV). The optimal coating time and concentrations were determined to achieve retention of vital blood components while preserving high water transport and optimal ciPTEC adhesion. The ciPTEC monolayers obtained were examined through immunocytochemistry to detect zona occludens 1 tight junction proteins. Reproducible monolayers were formed when using a combination of 2 mg ml(-1) 3,4-dihydroxy-l-phenylalanine (4 min coating, 1h dissolution) and 25 µg ml(-1) Coll IV (4 min coating). The successful transport of (14)C-creatinine through the developed living membrane system was used as an indication for organic cation transporter functionality. The addition of metformin or cimetidine significantly reduced the creatinine transepithelial flux, indicating active creatinine uptake in ciPTECs, most likely mediated by the organic cation transporter, OCT2 (SLC22A2). In conclusion, this study shows the successful development of a living membrane consisting of a reproducible ciPTEC monolayer on PES membranes, an important step towards the development of a bioartificial kidney.


Subject(s)
Kidney Tubules, Proximal/cytology , Membranes, Artificial , Polymers/pharmacology , Sulfones/pharmacology , Cell Adhesion/drug effects , Cell Line, Transformed , Coated Materials, Biocompatible/pharmacology , Collagen Type IV/pharmacology , Humans , Immunohistochemistry , Levodopa/pharmacology , Microscopy, Electron, Scanning , Permeability , Water
17.
Cell Rep ; 5(1): 126-36, 2013 Oct 17.
Article in English | MEDLINE | ID: mdl-24075988

ABSTRACT

Schwann cells are highly plastic cells that dedifferentiate to a progenitor-like state following injury. However, deregulation of this plasticity, may be involved in the formation of neurofibromas, mixed-cell tumors of Schwann cell (SC) origin that arise upon loss of NF1. Here, we show that adult myelinating SCs (mSCs) are refractory to Nf1 loss. However, in the context of injury, Nf1-deficient cells display opposing behaviors along the wounded nerve; distal to the injury, Nf1(-/-) mSCs redifferentiate normally, whereas at the wound site Nf1(-/-) mSCs give rise to neurofibromas in both Nf1(+/+) and Nf1(+/-) backgrounds. Tracing experiments showed that distinct cell types within the tumor derive from Nf1-deficient SCs. This model of neurofibroma formation demonstrates that neurofibromas can originate from adult SCs and that the nerve environment can switch from tumor suppressive to tumor promoting at a site of injury. These findings have implications for both the characterization and treatment of neurofibromas.


Subject(s)
Genes, Neurofibromatosis 1 , Neurofibromin 1/deficiency , Peripheral Nerve Injuries/genetics , Schwann Cells/pathology , Animals , Cell Growth Processes/physiology , MAP Kinase Signaling System , Mice , Mice, Inbred C57BL , Mice, Transgenic , Neurofibromatosis 1/genetics , Neurofibromatosis 1/metabolism , Neurofibromatosis 1/pathology , Neurofibromin 1/genetics , Neurofibromin 1/metabolism , Peripheral Nerve Injuries/metabolism , Peripheral Nerve Injuries/pathology , Schwann Cells/metabolism
18.
Curr Biol ; 22(19): 1765-73, 2012 Oct 09.
Article in English | MEDLINE | ID: mdl-22885065

ABSTRACT

BACKGROUND: The p53, Rb, and Ras/PI3K pathways are implicated in the development of the majority of human cancers. A number of studies have established that these pathways cooperate at the level of the cell cycle leading to loss of normal proliferative controls. Here we have investigated how these signals influence a second critical component of tumor formation-cell growth. RESULTS: We find that oncogenic Ras is sufficient to drive growth via the canonical growth pathway, PI3K-AKT-TOR; however, it does so relatively weakly and p53 loss does not drive cell growth at all. Importantly, we identify a novel role for the Rb family of tumor suppressors in directing cell growth via a signaling pathway distinct from PI3K-AKT-TOR and via an E2F-independent mechanism. However, we find that strong, sustained growth requires Rb loss together with Ras signaling, identifying an additional mechanism by which these oncogenic pathways cooperate and a critical role for Ras in preserving the uptake of extracellular nutrients required for biogenesis. CONCLUSIONS: We have identified a new role for the Rb family in cell biogenesis and show that, as for other processes associated with tumor development, oncogenic cell growth is dependent on cooperating oncogenes.


Subject(s)
Retinoblastoma Protein/metabolism , Schwann Cells/metabolism , Schwann Cells/pathology , ras Proteins/metabolism , Animals , Cell Cycle , Cell Proliferation , Cells, Cultured , E2F Transcription Factors/genetics , E2F Transcription Factors/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Rats , Retinoblastoma Protein/genetics , Signal Transduction , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , ras Proteins/genetics
19.
Neuron ; 73(4): 729-42, 2012 Feb 23.
Article in English | MEDLINE | ID: mdl-22365547

ABSTRACT

Following damage to peripheral nerves, a remarkable process of clearance and regeneration takes place. Axons downstream of the injury degenerate, while the nerve is remodeled to direct axonal regrowth. Schwann cells are important for this regenerative process. "Sensing" damaged axons, they dedifferentiate to a progenitor-like state, in which they aid nerve regeneration. Here, we demonstrate that activation of an inducible Raf-kinase transgene in myelinated Schwann cells is sufficient to control this plasticity by inducing severe demyelination in the absence of axonal damage, with the period of demyelination/ataxia determined by the duration of Raf activation. Remarkably, activation of Raf-kinase also induces much of the inflammatory response important for nerve repair, including breakdown of the blood-nerve barrier and the influx of inflammatory cells. This reversible in vivo model identifies a central role for ERK signaling in Schwann cells in orchestrating nerve repair and is a powerful system for studying peripheral neuropathies and cancer.


Subject(s)
MAP Kinase Signaling System/physiology , Nerve Regeneration/genetics , Peripheral Nerve Injuries/physiopathology , Proto-Oncogene Proteins c-raf/metabolism , Schwann Cells/physiology , Animals , Animals, Newborn , Benzamides/pharmacology , Cell Movement/drug effects , Cyclin D1/metabolism , Cytokines/metabolism , Diphenylamine/analogs & derivatives , Diphenylamine/pharmacology , Estrogen Antagonists/pharmacology , Gene Expression Regulation/drug effects , Gene Expression Regulation/genetics , Leukocytes/pathology , MAP Kinase Signaling System/drug effects , MAP Kinase Signaling System/genetics , Male , Mast Cells/pathology , Mice , Mice, Inbred C57BL , Mice, Transgenic , Microscopy, Confocal , Microscopy, Electron, Transmission , Microscopy, Immunoelectron , Motor Activity/drug effects , Motor Activity/genetics , Myelin Sheath/genetics , Myelin Sheath/metabolism , Nerve Regeneration/drug effects , Neutrophils/metabolism , Neutrophils/pathology , Peripheral Nerve Injuries/pathology , Proto-Oncogene Proteins c-raf/genetics , Reaction Time/drug effects , Reaction Time/genetics , Receptor, Nerve Growth Factor/genetics , Receptor, Nerve Growth Factor/metabolism , Receptors, Estrogen/genetics , Recovery of Function/drug effects , Recovery of Function/genetics , Schwann Cells/ultrastructure , T-Lymphocytes/metabolism , T-Lymphocytes/pathology , Tamoxifen/pharmacology , Time Factors
20.
Cell ; 143(1): 145-55, 2010 Oct 01.
Article in English | MEDLINE | ID: mdl-20869108

ABSTRACT

The peripheral nervous system has astonishing regenerative capabilities in that cut nerves are able to reconnect and re-establish their function. Schwann cells are important players in this process, during which they dedifferentiate to a progenitor/stem cell and promote axonal regrowth. Here, we report that fibroblasts also play a key role. Upon nerve cut, ephrin-B/EphB2 signaling between fibroblasts and Schwann cells results in cell sorting, followed by directional collective cell migration of Schwann cells out of the nerve stumps to guide regrowing axons across the wound. Mechanistically, we find that cell-sorting downstream of EphB2 is mediated by the stemness factor Sox2 through N-cadherin relocalization to Schwann cell-cell contacts. In vivo, loss of EphB2 signaling impaired organized migration of Schwann cells, resulting in misdirected axonal regrowth. Our results identify a link between Ephs and Sox proteins, providing a mechanism by which progenitor cells can translate environmental cues to orchestrate the formation of new tissue.


Subject(s)
Nerve Regeneration , Peripheral Nerves/physiology , Receptor, EphB2/metabolism , SOXB1 Transcription Factors/metabolism , Schwann Cells/physiology , Animals , Axons/metabolism , Cadherins/metabolism , Cell Movement , Extracellular Matrix/metabolism , Fibroblasts/physiology , Rats , Schwann Cells/cytology , Signal Transduction
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