Ultrastructural and Molecular Investigation on Peripheral Leukocytes in Alzheimer's Disease Patients.

Thriving literature underlines white blood cell involvement in the inflammatory processes of Alzheimer's Disease (AD). Among leukocytes, lymphocytes have been considered sentinels of neuroinflammation for years, but recent findings highlighted the pivotal role of neutrophils. Since neutrophils that infiltrate the brain through the brain vascular vessels may affect the immune function of microglia in the brain, a close investigation of the interaction between these cells is important in understanding neuroinflammatory phenomena and the immunological aftermaths that follow. This study aimed to observe how peripheral leukocyte features change at different stages of AD to identify potential molecular markers when the first features of pathological neurodegeneration arise. For this purpose, the examined patients were divided into Mild Cognitive Impairment (MCI) and severely impaired patients (DAT) based on their Cognitive Dementia Rating (CDR). The evaluation of the neutrophil-to-lymphocytes ratio and the morphology and function of leukocytes showed a close relationship between the ultrastructural and the molecular features in AD progression and suggested putative markers for the early stages of the disease.

Effect of RNS60 in amyotrophic lateral sclerosis: a phase II multicentre, randomized, double-blind, placebo-controlled trial.

BACKGROUND AND PURPOSE: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with limited treatment options. RNS60 is an immunomodulatory and neuroprotective investigational product that has shown efficacy in animal models of ALS and other neurodegenerative diseases. Its administration has been safe and well tolerated in ALS subjects in previous early phase trials. METHODS: This was a phase II, multicentre, randomized, double-blind, placebo-controlled, parallel-group trial. Participants diagnosed with definite, probable or probable laboratory-supported ALS were assigned to receive RNS60 or placebo administered for 24 weeks intravenously (375 ml) once a week and via nebulization (4 ml/day) on non-infusion days, followed by an additional 24 weeks off-treatment. The primary objective was to measure the effects of RNS60 treatment on selected biomarkers of inflammation and neurodegeneration in peripheral blood. Secondary objectives were to measure the effect of RNS60 on functional impairment (ALS Functional Rating Scale-Revised), a measure of self-sufficiency, respiratory function (forced vital capacity, FVC), quality of life (ALS Assessment Questionnaire-40, ALSAQ-40) and survival. Tolerability and safety were assessed. RESULTS: Seventy-four participants were assigned to RNS60 and 73 to placebo. Assessed biomarkers did not differ between arms. The mean rate of decline in FVC and the eating and drinking domain of ALSAQ-40 was slower in the RNS60 arm (FVC, difference 0.41 per week, standard error 0.16, p = 0.0101; ALSAQ-40, difference -0.19 per week, standard error 0.10, p = 0.0319). Adverse events were similar in the two arms. In a post hoc analysis, neurofilament light chain increased over time in bulbar onset placebo participants whilst remaining stable in those treated with RNS60. CONCLUSIONS: The positive effects of RNS60 on selected measures of respiratory and bulbar function warrant further investigation.

Blood Analytes as Biomarkers of Mechanisms Involved in Alzheimer's Disease Progression.

Alzheimer's disease (AD) is the leading cause of dementia, but the pathogenetic factors are not yet well known, and the relationships between brain and systemic biochemical derangements and disease onset and progression are unclear. We aim to focus on blood biomarkers for an accurate prognosis of the disease. We used a dataset characterized by longitudinal findings collected over the past 10 years from 90 AD patients. The dataset included 277 observations (both clinical and biochemical ones, encompassing blood analytes encompassing routine profiles for different organs, together with immunoinflammatory and oxidative markers). Subjects were grouped into four severity classes according to the Clinical Dementia Rating (CDR) Scale: mild (CDR = 0.5 and CDR = 1), moderate (CDR = 2), severe (CDR = 3) and very severe (CDR = 4 and CDR = 5). Statistical models were used for the identification of potential blood markers of AD progression. Moreover, we employed the Pathfinder tool of the Reactome database to investigate the biological pathways in which the analytes of interest could be involved. Statistical results reveal an inverse significant relation between four analytes (high-density cholesterol, total cholesterol, iron and ferritin) with AD severity. In addition, the Reactome database suggests that such analytes could be involved in pathways that are altered in AD progression. Indeed, the identified blood markers include molecules that reflect the heterogeneous pathogenetic mechanisms of AD. The combination of such blood analytes might be an early indicator of AD progression and constitute useful therapeutic targets.

Effects of Global Warming on Patients with Dementia, Motor Neuron or Parkinson's Diseases: A Comparison among Cortical and Subcortical Disorders.

Exposure to global warming can be dangerous for health and can lead to an increase in the prevalence of neurological diseases worldwide. Such an effect is more evident in populations that are less prepared to cope with enhanced environmental temperatures. In this work, we extend our previous research on the link between climate change and Parkinson's disease (PD) to also include Alzheimer's Disease and other Dementias (AD/D) and Amyotrophic Lateral Sclerosis/Motor Neuron Diseases (ALS/MND). One hundred and eighty-four world countries were clustered into four groups according to their climate indices (warming and annual average temperature). Variations between 1990 and 2016 in the diseases' indices (prevalence, deaths, and disability-adjusted life years) and climate indices for the four clusters were analyzed. Unlike our previous work on PD, we did not find any significant correlation between warming and epidemiological indices for AD/D and ALS/MND patients. A significantly lower increment in prevalence in countries with higher temperatures was found for ALS/MND patients. It can be argued that the discordant findings between AD/D or ALS/MND and PD might be related to the different features of the neuronal types involved and the pathophysiology of thermoregulation. The neurons of AD/D and ALS/MND patients are less vulnerable to heat-related degeneration effects than PD patients. PD patients' substantia nigra pars compacta (SNpc), which are constitutively frailer due to their morphology and function, fall down under an overwhelming oxidative stress caused by climate warming.

Raman spectroscopy and multivariate analysis as potential tool to follow Alzheimer's disease progression.

Raman spectroscopy is an emerging tool in the research and diagnosis of different diseases, including neurodegenerative disorders. In this work, blood serum samples collected from healthy controls and dementia patients were analysed by Raman spectroscopy to develop a classification model for the diagnosis of dementia of Alzheimer's type (DAT). Raman spectra were processed by means of multivariate tools for multivariate analysis. Lower concentration levels of carotenoids were detected in blood serum from patients, which allowed for a good discrimination with respect to controls, such as 93% of correct predictions on the test set with random forest. We also hypothesize that carotenoid levels might be informative about the severity and progression of the disease, since the intensity of carotenoid signals decreased from the early stage to more severe patients. These encouraging results suggest the possibility to use Raman spectroscopy for the analysis of alternative biofluids (e.g. saliva) and the unobtrusive diagnosis of other neurodegenerative disorders.

Climate change and neurodegenerative diseases.

The climate change induced global warming, and in particular the increased frequency and intensity of heat waves, have been linked to health problems. Among them, scientific works have been reporting an increased incidence of neurological diseases, encompassing also neurodegenerative ones, such as Dementia of Alzheimer's type, Parkinson's Disease, and Motor Neuron Diseases. Although the increase in prevalence of neurodegenerative diseases is well documented by literature reports, the link between global warming and the enhanced prevalence of such diseases remains elusive. This is the main theme of our work, which aims to examine the connection between high temperature exposure and neurodegenerative diseases. Firstly, we evaluate the influence of high temperatures exposure on the pathophysiology of these disorders. Secondly, we discuss its effects on the thermoregulation, already compromised in affected patients, and its interference with processes of excitotoxicity, oxidative stress and neuroinflammation, all of them related with neurodegeneration. Finally, we investigate chronic versus acute stressors on body warming, and put forward a possible interpretation of the beneficial or detrimental effects on the brain, which is responsible for the incidence or progression of neurological disorders.

Using blood data for the differential diagnosis and prognosis of motor neuron diseases: a new dataset for machine learning applications.

Early differential diagnosis of several motor neuron diseases (MNDs) is extremely challenging due to the high number of overlapped symptoms. The routine clinical practice is based on clinical history and examination, usually accompanied by electrophysiological tests. However, although previous studies have demonstrated the involvement of altered metabolic pathways, biomarker-based monitoring tools are still far from being applied. In this study, we aim at characterizing and discriminating patients with involvement of both upper and lower motor neurons (i.e., amyotrophic lateral sclerosis (ALS) patients) from those with selective involvement of the lower motor neuron (LMND), by using blood data exclusively. To this end, in the last ten years, we built a database including 692 blood data and related clinical observations from 55 ALS and LMND patients. Each blood sample was described by 108 analytes. Starting from this outstanding number of features, we performed a characterization of the two groups of patients through statistical and classification analyses of blood data. Specifically, we implemented a support vector machine with recursive feature elimination (SVM-RFE) to automatically diagnose each patient into the ALS or LMND groups and to recognize whether they had a fast or slow disease progression. The classification strategy through the RFE algorithm also allowed us to reveal the most informative subset of blood analytes including novel potential biomarkers of MNDs. Our results show that we successfully devised subject-independent classifiers for the differential diagnosis and prognosis of ALS and LMND with remarkable average accuracy (up to 94%), using blood data exclusively.

Drought stress modulates secondary metabolites in Brassica oleracea L. convar. acephala (DC) Alef, var. sabellica L.

BACKGROUND: Consumer preference today is for the consumption of functional food and the reduction of chemical preservatives. Moreover, the antimicrobial properties and health-promoting qualities of plant secondary metabolites are well known. Due to forecasted climate changes and increasing human population, agricultural practices for saving water have become a concern. In the present study, the physiological responses of curly kale Brassica oleracea L. convar. Acephala (DC) var. sabellica to drought stress and the impact of water limitation on the concentration of selected secondary metabolites were investigated under laboratory-controlled conditions. RESULTS: Results indicated that drought stress increased the content of trans-2-hexenal, phytol and δ-tocopherol, and decreased chlorophyll content. Moreover, drought stress increased antioxidant capacity and the expression of AOP2, a gene associated with the biosynthesis of aliphatic alkenyl glucosinolates, and of three genes - TGG1, TGGE and PEN2 - encoding for myrosinases, the enzymes involved in glucosinolate breakdown. CONCLUSION: The present study shows that water limitation during the growing phase might be exploited as a sustainable practice for producing curly kale with a high concentration of nutritionally important health-promoting bioactive metabolites. © 2019 Society of Chemical Industry.

Activation of the interferon type I response rather than autophagy contributes to myogenesis inhibition in congenital DM1 myoblasts.

Congenital myotonic dystrophy type 1 (CDM1) is characterized by severe symptoms that affect patients from birth, with 40% mortality in the neonatal period and impaired skeletal muscle development. In this paper, we examined the relationship between autophagy and abnormal myogenic differentiation of CDM1 myoblasts. We investigated these pathological features at both ultrastructural and molecular levels, utilizing two CDM1 foetal myoblasts, CDM13 and CDM15, with 1800 and 3200 repeats, respectively. The congenital nature of these CDM1 myoblasts was confirmed by the high methylation level at the DMPK locus. Our results indicated that abnormal autophagy was independent of myogenic differentiation, as CDM13 myoblasts differentiated as well as control myoblasts but underwent autophagy like CDM15, displaying impaired differentiation. miRNA expression profiles revealed that CDM15 myoblasts failed to upregulate the complex network of myo-miRNAs under MYOD and MEF2A control, while this network was upregulated in CDM13 myoblasts. Interestingly, the abnormal differentiation of CDM15 myoblasts was associated with cellular stress accompanied by the induction of the interferon type 1 pathway (innate immune response). Indeed, inhibition of the interferon (IFN) type I pathway restores myogenic differentiation of CDM15 myoblasts, suggesting that the inappropriate activation of the innate immune response might contribute to impaired myogenic differentiation and severe muscle symptoms observed in some CDM1 patients. These findings open up the possibility of new therapeutic approaches to treat CDM1.

Analysis of extracellular vesicles produced in the biofilm by the dimorphic yeast Pichia fermentans.

The yeast Pichia fermentans DISAABA 726 strain (P. fermentans) is a dimorphic yeast that under different environmental conditions may switch from a yeast-like to pseudohyphal morphology. We hypothesize that exosomes-like vesicles (EV) could mediate this rapid modification. EV are membrane-derived vesicles carrying lipids, proteins, mRNAs and microRNAs and have been recognized as important mediators of intercellular communication. Although it has been assumed for a long time that fungi release EV, knowledge of their functions is still limited. In this work we analyze P. fermentans EV production during growth in two different media containing urea (YCU) or methionine (YCM) where yeast-like or pseudohyphal morphology are produced. We developed a procedure to extract EV from the neighboring biofilm which is faster and more efficient as compared to the widely used ultracentrifugation method. Differences in morphology and RNA content of EV suggest that they might have an active role during dimorphic transition as response to the growth conditions. Our findings are coherent with a general state of hypoxic stress of the pseudohyphal cells.

A L-type lectin gene is involved in the response to hormonal treatment and water deficit in Volkamer lemon.

Combination of biotic and abiotic stress is a major challenge for crop and fruit production. Thus, identification of genes involved in cross-response to abiotic and biotic stress is of great importance for breeding superior genotypes. Lectins are glycan-binding proteins with a functions in the developmental processes as well as in the response to biotic and abiotic stress. In this work, a lectin like gene, namely ClLectin1, was characterized in Volkamer lemon and its expression was studied in plants exposed to either water stress, hormonal elicitors (JA, SA, ABA) or wounding to understand whether this gene may have a function in the response to multiple stress combination. Results showed that ClLectin1 has 100% homology with a L-type lectin gene from C. sinensis and the in silico study of the 5'UTR region showed the presence of cis-responsive elements to SA, DRE2 and ABA. ClLectin1 was rapidly induced by hormonal treatments and wounding, at local and systemic levels, suggesting an involvement in defence signalling pathways and a possible role as fast detection biomarker of biotic stress. On the other hand, the induction of ClLectin1 by water stress pointed out a role of the gene in the response to drought. The simultaneous response of ClLectin1 expression to water stress and SA treatment could be further investigated to assess whether a moderate drought stress may be useful to improve citrus performance by stimulating the SA-dependent response to biotic stress.

Effect of itraconazole on mouse mesencephalic neurons.

Neuronal cells have complex geometrical shapes, long processes such as axons and dendrites, and as a response to specific stimuli, they go through polarized neuronal migration that influences connectivity and information processing. Recently, it has been discovered that itraconazole, a widely used systemic antifungal drug, has an effect on cell morphology, acting as an inhibitor of the morphogen Sonic Hedgehog (Shh) and of the mammalian target of rapamycin mTOR pathways. In this paper we evaluated the effect of itraconazole on mouse mesencephalic dopaminergic neurons following their neurite outgrowth and functional activity by [(3)H] DA uptake. Furthermore the expression of several neural markers, the activation of the mTOR and of the morphogenic Shh pathways in the neuronal population was examined. Our results show for the first time a strong alteration of neurons morphology and an inhibitory effect of differentiation by itraconazole, probably due to cholesterol trafficking reduction, mTOR and Shh pathways inhibition. The inhibition of mTOR and Shh pathways by this drug has also been found in other cellular systems such as endothelial cells and lung cancer cells, suggesting a conserved mechanism of intercellular communication. As itraconazole is currently involved in multiple human clinical trials as a prospective anticancer agent, the effect on neuronal differentiation should be taken into account.

Proteome changes during yeast-like and pseudohyphal growth in the biofilm-forming yeast Pichia fermentans.

The Pichia fermentans strain DISAABA 726 is a biofilm-forming yeast that has been proposed as biocontrol agent to control brown rot on apple. How ever, when inoculated on peach, strain 726 shows yeast-like to pseudohyphal transition coupled to a pathogenic behaviour. To identify the proteins potentially involved in such transition process, a comparative proteome analysis of P. fermentans 726 developed on peach (filamentous growth) vs apple (yeast-like growth) was carried out using two-dimensional gel electrophoresis coupled with mass spectrometry analysis. The proteome comparison was also performed between the two different cell morphologies induced in a liquid medium amended with urea (yeast-like cells) or methionine (filamentous cells) to exclude fruit tissue impact on the transition. Seventy-three protein spots showed significant variations in abundance (±twofold, p < 0.01, confidence intervals 99 %) between pseudohyphal vs yeast-like morphology produced on fruits. Among them, 30 proteins changed their levels when the two morphologies were developed in liquid medium. The identified proteins belong to several pathways and functions, such as glycolysis, amino acid synthesis, chaperones, and signalling transduction. The possible role of a group of proteins belonging to the carbohydrate pathway in the metabolic re-organisation during P. fermentans dimorphic transition is discussed.

Salt-stress induced changes in the leaf proteome of diploid and tetraploid mandarins with contrasting Na+ and Cl- accumulation behaviour.

To understand the genotypic variation of citrus to mild salt stress, a proteomic approach has been carried out in parallel on two citrus genotypes ('Cleopatra' and 'Willow leaf' mandarins), which differ for Na(+) and Cl(-) accumulation, and their cognate autotetraploids (4×). Using two-dimensional electrophoresis approximately 910 protein spots were reproducibly detected in control and salt-stressed leaves of all genotypes. Among them, 44 protein spots showing significant variations at least in one genotype were subjected to mass spectrometry analysis for identification. Salt-responsive proteins were involved in several functions, including photosynthetic processes, ROS scavenging, stress defence, and signalling. Genotype factors affect the salt-responsive pattern, especially that of carbon metabolism. The no ion accumulator 'Cleopatra' mandarin genotype showed the highest number of salt-responsive proteins, and up-regulation of Calvin cycle-related proteins. Conversely the ion accumulator 'Willow leaf' mandarin showed high levels of several photorespiration-related enzymes. A common set of proteins (twelve spots) displayed higher levels in salt-stressed leaves of 2× and 4× 'Cleopatra' and 4× 'Willow leaf' mandarin. Interestingly, antioxidant enzymes and heat shock proteins showed higher constitutive levels in 4× 'Cleopatra' mandarin and 4× 'Willow leaf' mandarin compared with the cognate 2× genotype. This work provides for the first time information on the effect of 8 weeks of salt stress on citrus genotypes contrasting for ion accumulation and their cognate autotetraploids. Results underline that genetic factors have a predominant effect on the salt response, although a common stress response independent from genotype was also found.

Itraconazole inhibits HMEC-1 angiogenesis.

Abnormal angiogenesis is implicated in a number of human diseases and endothelial growth inhibition represents a common approach in tumor therapy. Recently itraconazole, frequently used in humans as antifungal drug, which blocks the biosynthesis of cholesterol, has been found to be antiangiogenic in primary umbilical vein endothelial cells. However, the exact antiangiogenic mechanisms remain largely unknown. In this paper, we studied the effect of itraconazole in human dermal microvascular endothelial cells (HMEC-1), an immortalized cell line to study adult angiogenesis. A 50% reduction of microtubule formation was observed after itraconazole treatment which was partially rescued by cholesterol addition. We found that itraconazole inhibits angiogenesis markers such as VEGF, AAMP and e-NOS. mTOR and ERK1/2 phosphorylation as well as the expression of Gli1, one of the main controllers of the Shh pathway, were also inhibited by itraconazole. Cholesterol addition did not completely rescue inhibition of these pathways, suggesting that the itraconazole antiangiogenic activity could be due to multiple mechanisms. Our results may contribute to novel approaches to block angiogenesis with therapeutic application.

Proangiogenic effect of TSH in human microvascular endothelial cells through its membrane receptor.

CONTEXT: TSH, which acts via specific cell membrane TSH receptors (TSHR), is regarded as a thyroid-specific growth factor. Recently, the presence of TSHR has been reported in extrathyroid tissues, but the role of TSH in nonthyroid tissue is unknown. OBJECTIVE: Our objective was to study the direct effect of TSH on angiogenesis in a human dermal microvascular endothelial cell line (HMEC-1). Parallel experiments were conducted with human primary cardiac microvascular endothelial cells (HMVEC-C). DESIGN: TSHR in HMEC-1 was measured by immunofluorescence, Western blot, and RT-PCR and its functional activity by variation of intracellular cAMP concentrations. The expression of some angiogenic genes and angiogenic signaling pathways was also evaluated after TSH treatment. Assays of cell proliferation and capillary network formation on collagen or Matrigel were performed in HMEC-1 cells and HMVEC-C. RESULTS: We showed the presence of TSHR in HMEC-1 cells. Increased intracellular cAMP concentrations after TSH treatment indicated the TSHR to be functional. TSH enhanced proliferation and stimulated capillary network formation in HMEC-1, whereas antibodies against vascular endothelial growth factor (VEGF) and TSHR abolished this effect. TSH increased AAMP, VEGF, and eNOS expression. TSH induced phosphorylation of protein kinase S6K1, whereas TSHR blocking antibodies inhibited the phosphorylation of the protein kinase S6K1. A similar effect of TSH on capillary network formation was observed in HMVEC-C. CONCLUSION: Our findings provide strong evidence for a direct effect of TSH on angiogenesis through its receptor, via cAMP-mammalian target of rapamycin signaling and indicate that this effect is VEGF dependent.

A stress responsive alternative splicing mechanism in Citrus clementina leaves.

Chitinases are often considered pathogenesis-related proteins since their activity can be induced by viral infections, fungal and bacterial cell wall components, and also by more general sources of stress such as wounding, salicylic acid, ethylene, auxins and cytokinins. In the present study, comparative proteomic analysis showed the defense-related acidic chitinase II to be specifically induced in Citrus clementina leaves infested by the two-spotted spider mite Tetranychus urticae or treated with MeJA. In parallel, changes in the mRNA profiles of two partially homologous chitinase forms were shown by RT-PCR. In particular, the appearance of an additional cDNA chitinase fragment in T. urticae-infested and MeJA-treated leaves was observed. This finding may indicate a specific regulatory mechanism of chitinase expression. We report evidence for alternative splicing in T. urticae-infested C. clementina, where a premature stop codon after the first 135 amino acids was introduced. We observed inducible chitinase activity after MeJA treatment, indicative of a rapid plant response to infestation. This work provides the first evidence of chitinase alternative splicing in C. clementina. In addition, the presence of the dual-band pattern for chitinase cDNA by RT-PCR may represent a suitable predictive marker for early diagnosis of plant biotic stress.

Altered signal transduction pathways and induction of autophagy in human myotonic dystrophy type 1 myoblasts.

Congenital myotonic dystrophy type 1 (CDM1) affects patients from birth and is associated with mental retardation and impaired muscle development. CDM1 patients carry 1000-3000 CTG repeats in the DMPK gene and display defective skeletal muscles differentiation, resulting in reduced size of myotubes and decreased number of satellite cells. In this study, human myoblasts in culture deriving from control and DM1 embryos (3200 CTG repeats) were analyzed using both a biochemical and electron microscopic approach, in order to provide new insights into the molecular mechanisms underlying such alteration. Interestingly, electron microscopy analysis showed not only ultrastructural features of abnormal differentiation but also revealed the presence of autophagic vacuoles in DM1 myoblasts not undergoing differentiation. In accordance with the electron microscopic findings, the autophagic markers LC3 and ATG5, but not apoptotic markers, were significantly up regulated in DM1 myoblasts after differentiating medium addition. The induction of autophagic processes in DM1 myoblasts was concomitant to p53 over-expression and inhibition of the mTOR-S6K1 pathway, causatively involved in autophagy. Moreover biochemical alterations of the two main signal transduction pathways involved in differentiation were observed in DM1 myoblasts, in particular decreased activation of p38MAPK and persistent activation of the MEK-ERK pathway. This work, while demonstrating that major signaling pathways regulating myoblasts differentiation are profoundly deranged in DM1 myoblasts, for the first time provides evidence of autophagy induction, possibly mediated by p53 activation in response to metabolic stress which might contribute to the dystrophic alterations observed in the muscles of congenital DM1 patients.

TSH induces co-localization of TSH receptor and Na/K-ATPase in human erythrocytes.

Thyroid stimulating hormone (TSH) binds to a specific TSH receptor (TSHR) which activates adenylate cyclase and increases cAMP levels in thyroidal cells. Recent studies have reported the presence of TSH receptor in several extra-thyroidal cell types, including erythrocytes. We have previously suggested that TSH is able to influence the erythrocyte Na/K-ATPase ouabain binding properties through a receptor mediated mechanism. The direct interaction of TSH receptor with the Na/K-pump and a functional role of TSHR in erythrocytes was not demonstrated. The interaction of TSH receptor with Na/K-pump and a TSHR functional role are not yet demonstrated in erythrocytes. In this study, we examined the interaction between the two receptors after TSH treatment using immunofluorescence coupled to confocal microscopy and a co-immunoprecipitation technique. The cAMP dependent signalling after TSH treatment was measured to verify TSHR functionality. We found that TSH receptor and Na/K-ATPase are localized on the membranes of both erythrocytes and erythrocyte ghosts; TSH receptor responds to TSH treatment by increasing intracellular cAMP levels from two to tenfold. In ghost membranes TSH treatment enhances up to three fold co-localization of TSHR with Na/K-ATPase and co-immunoprecipitation confirms their direct physical interaction. In conclusion our results are compatible with the existence, in erythrocytes, of a functional TSHR that interacts with Na/K-ATPase after TSH treatment, thus suggesting a novel cell signalling pathway, potentially active in local circulatory control.

Presence of a functional TSH receptor on human erythrocytes.

The presence of thyrotropin receptors (TSHR) has been reported in some extrathyroidal tissues but its physio-pathological role still remains unclear. TSH (seems to) affects the human erythrocytes Na(+)/K(+)-ATPase in vitro, however receptors on erythrocytes have not yet been described. In this work the effect of recombinant human TSH (rhTSH) on sites number and activity of erythrocyte Na(+)/K(+)-ATPase was investigated in a group of thyroidectomized patient enrolled for rhTSH test. As detected by (3)H-ouabain binding, rhTSH administration induced a significant increase in the number of sites (p=0.005) and in the Kd (p=0.006) of Na(+)/K(+)-ATPase. rhTSH did not induce significant difference in Na(+)/K(+)-ATPase activity measured by (86)Rb uptake. (125)I-TSH binding studies and Western blotting data showed the existence of TSHR in the erythrocytes of healthy donors. In conclusion The TSH action on Na(+)/K(+)-ATPase of human erythrocytes can be explained by the presence of TSHR.