The co-creation, initial piloting, and protocol for a cluster randomised controlled trial of a coach-led positive body image intervention for girls in sport.

BACKGROUND: Globally, girls disengage from sports at an earlier age and higher rate than boys. This is, in part, due to the unique body image challenges that girls face, relative to their male peers. Existing intervention efforts that aim to reduce girls' negative body image and movement experiences have proven marginally effective, if not ineffective. This paper outlines the co-creation, initial piloting and protocol for a cluster randomised controlled trial of Body Confident Athletes (BCA); an in-person, coach-led intervention that aims to foster positive body image and sports enjoyment among girls. METHODS: Following co-creation and an initial pilot, a two-armed cluster randomised controlled trial will assess the immediate (post-intervention) and short-term (1-month and 3-month follow-up) impact of BCA on girls' (N = 1,036; 11-17 years old) body image, sports enjoyment, and affect. Sport organisations will be randomly allocated (1:1) into either an intervention or waitlist control condition. Girls and coaches in the intervention condition will complete three 60-minute sessions over three consecutive weeks. The primary outcome will be the immediate change in girls' body esteem, with secondary outcomes assessing the immediate and short-term changes in girls' body appreciation, self-objectification, attuned self-care, sports enjoyment, and affect. DISCUSSION: This research is the first to utilise an international multi-stakeholder partnership to co-create and evaluate an intervention that addresses the intersection of girls' body image and sport experiences. The theoretical and methodological considerations of this research have led to a feasible intervention and trial protocol, and if proven effective, BCA may assist in reducing the global gender disparity in sports participation. TRIAL REGISTRATION NUMBER: NCT05594524 , registered 25th October 2022.

The effects of cognitive and behavioural therapies for anxiety disorders on depression: a meta-analysis.

BACKGROUND: The effects of cognitive behavioural therapy of anxiety disorders on depression has been examined in previous meta-analyses, suggesting that these treatments have considerable effects on depression. In the current meta-analysis we examined whether the effects of treatments of anxiety disorders on depression differ across generalized anxiety disorder (GAD), social anxiety disorder (SAD) and panic disorder (PD). We also compared the effects of these treatments with the effects of cognitive and behavioural therapies of major depression (MDD). METHOD: We searched PubMed, PsycINFO, EMBASE and the Cochrane database, and included 47 trials on anxiety disorders and 34 trials on MDD. RESULTS: Baseline depression severity was somewhat lower in anxiety disorders than in MDD, but still mild to moderate in most studies. Baseline severity differed across the three anxiety disorders. The effect sizes found for treatment of the anxiety disorders ranged from g = 0.47 for PD, g = 0.68 for GAD and g = 0.69 for SAD. Differences between these effect sizes and those found in the treatment of MDD (g = 0.81) were not significant in most analyses and we found few indications that the effects differed across anxiety disorders. We did find that within-group effect sizes resulted in significantly (p < 0.001) larger effect sizes for depression (g = 1.50) than anxiety disorders (g = 0.73-0.91). Risk of bias was considerable in the majority of studies. CONCLUSIONS: Patients participating in trials of cognitive behavioural therapy for anxiety disorders have high levels of depression. These treatments have considerable effects on depression, and these effects are comparable to those of treatment of primary MDD.

Brain connectivity is altered by extreme physical exercise during non-REM sleep and wakefulness: indications from EEG and fMRI studies.

Brain connectivity is associated to behavioral states (e.g. wake, sleep) and modified by physical activity although, to date, it is not clear which components (e.g. hypothalamus-pituitary-adrenal axis hormones, cytokines) associated to the exercise are involved. In this pilot study, we used extreme exercise (UltraTriathlon) as a model to investigate physical-activity-related changes of brain connectivity. We studied post-race brain synchronization during wakefulness and sleep as well as possible correlations between exercise-related cytokines/hormones and synchronization features. For wakefulness, global synchronization was evaluated by estimating from fMRI data (12 athletes) the brain global connectivity (GC). GC increased in several brain regions, mainly related to sensory-motor activity, emotional modulation and response to stress that may foster rapid exchange of information across regions, and reflect post-race internally-focused mental activity or disengagement from previous motor programs. No significant correlations between cytokines/hormones and GC were found. For sleep (8 athletes), synchronization was evaluated by estimating the local-(cortical) and global-related (thalamo- cortical) EEG features associated to the phenomenon of Sleep Slow Oscillations (SSO) of NREM sleep. Results showed that: power of fast rhythms in the baseline preceding the SSO increased in midline and parietal regions; amplitude and duration of SSOs increased, mainly in posterior areas; sigma modulation in the SSO up state decreased. In the post race, IL-10 positively correlated with fast rhythms baseline, SSO rate and positive slope; IL-1ra and cortisol inversely correlated with SSO duration; TNF-α and C-reactive protein positively correlated with fast rhythm modulation in the SSO up state. Sleep results suggest that: arousal during sleep, estimated by baseline fast rhythms, is increased; SSO may be sustained by cortical excitability, linked to anti-inflammatory markers (IL-10); thalamo-cortical entrainment, (sigma modulation), is impaired in athletes with higher inflammatory markers.

Scaffold-assisted cartilage tissue engineering using infant chondrocytes from human hip cartilage.

OBJECTIVE: Studies about cartilage repair in the hip and infant chondrocytes are rare. The aim of our study was to evaluate the use of infant articular hip chondrocytes for tissue engineering of scaffold-assisted cartilage grafts. METHOD: Hip cartilage was obtained from five human donors (age 1-10 years). Expanded chondrocytes were cultured in polyglycolic acid (PGA)-fibrin scaffolds. De- and re-differentiation of chondrocytes were assessed by histological staining and gene expression analysis of typical chondrocytic marker genes. In vivo, cartilage matrix formation was assessed by histology after subcutaneous transplantation of chondrocyte-seeded PGA-fibrin scaffolds in immunocompromised mice. RESULTS: The donor tissue was heterogenous showing differentiated articular cartilage and non-differentiated tissue and considerable expression of type I and II collagens. Gene expression analysis showed repression of typical chondrocyte and/or mesenchymal marker genes during cell expansion, while markers were re-induced when expanded cells were cultured in PGA-fibrin scaffolds. Cartilage formation after subcutaneous transplantation of chondrocyte loaded PGA-fibrin scaffolds in nude mice was variable, with grafts showing resorption and host cell infiltration or formation of hyaline cartilage rich in type II collagen. Addition of human platelet rich plasma (PRP) to cartilage grafts resulted robustly in formation of hyaline-like cartilage that showed type II collagen and regions with type X collagen. CONCLUSION: These results suggest that culture of expanded and/or de-differentiated infant hip cartilage cells in PGA-fibrin scaffolds initiates chondrocyte re-differentiation. The heterogenous donor tissue containing immature chondrocytes bears the risk of cartilage repair failure in vivo, which may be possibly overcome by the addition of PRP.

Epigallocatechin gallate, folic acid, vitamin B12, and hyaluronic acid significantly increase apoptosis and p53 expression in HeLa cells.

OBJECTIVE: The human papilloma virus (HPV) is the etiological agent of cervical cancer in more than 95% of cases worldwide. Although most HPV infections clear up on their own and most pre-cancerous lesions spontaneously resolve, in some cases, they can persist, leading to lesions which may progress towards invasive cervical cancer. MATERIALS AND METHODS: We evaluated the effects of the association of epigallocatechin gallate (EGCG) + folic acid (FA) + vitamin B12 (B12) + hyaluronic acid (HA) on HPV-positive cervical cancer cells (HeLa). RESULTS: The association of EGCG + FA + B12 + HA induced a significant increase of apoptosis and p53 gene expression with a concomitant decrease of E6/E7 gene expression, a marker of HPV infection. CONCLUSIONS: This study provides for the first-time evidence on the potential additive activity of EGCG + FA + B12 + HA in counteracting HPV infection, by increasing apoptosis and p53 expression in HPV-infected cervical HeLa cells.

Author Correction: Epigallocatechin gallate, folic acid, vitamin B12, and hyaluronic acid significantly increase apoptosis and p53 expression in HeLa cells.

Correction to: Eur Rev Med Pharmacol Sci 2023; 27 (11): 5240-5245-DOI: 10.26355/eurrev_202306_32642-PMID: 37318498-published online on June 13, 2023. After publication, the authors discovered that Prof. C. Gentili's affiliation was wrong as he has never been a member of the Italian Society of Colposcopy and Cervicovaginal Pathology (SICPCV). The authors never found the mistake during the review process nor requested a correction before publication. Therefore, the second affiliation has been corrected as follows: Pathologist, Independent Practitioner, Carrara, Italy. There are amendments to this paper. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/32642.

Fatal case of human rabies imported to Italy from India highlights the importance of adequate post-exposure prophylaxis, October 2011.

In October 2011, an Indian man resident in Italy was admitted to a hospital in Mantua, Italy with symptoms of acute encephalitis. Due to a recent history of bite by a suspected rabid dog in India, where he had received incomplete post-exposure treatment, rabies was suspected. The patient died after 22 days of intensive care treatment and rabies was confirmed post mortem. This report stresses the need of appropriate post-exposure prophylaxis in rabies-endemic countries.

Classifying subclinical depression using EEG spectral and connectivity measures.

Detecting depression on its early stages helps preventing the onset of severe depressive episodes. In this study, we propose an automatic classification pipeline to detect subclinical depression (i.e., dysphoria) through the electroencephalography (EEG) signal. To this aim, we recorded the EEG signals in resting condition from 26 female participants with dysphoria and 38 female controls. The EEG signals were processed to extract several spectral and functional connectivity features to feed a nonlinear Support Vector Machine (SVM) classifier embedded with a Recursive Feature Elimination (RFE) algorithm. Our recognition pipeline obtained a maximum classification accuracy of 83.91% in recognizing dysphoria patients with a combination of connectivity and spectral measures. Moreover, an accuracy of 76.11% was achieved with only the 4 most informative functional connections, suggesting a central role of cortical connectivity in the theta band for early depression recognition. The present study can facilitate the diagnosis of subclinical conditions of depression and may provide reliable indicators of depression for the clinical community.

Hypertrophic chondrocytes undergo further differentiation in culture.

Conditions have been defined for promoting growth and differentiation of hypertrophic chondrocytes obtained in culture starting from chick embryo tibiae. Hypertrophic chondrocytes, grown in suspension culture as described (Castagnola P., G. Moro, F. Descalzi Cancedda, and R. Cancedda. 1986. J. Cell Biol. 102:2310-2317), when they reached the stage of single cells, were transferred to substrate-dependent culture conditions in the presence of ascorbic acid. Cells showed a change in morphology, became more elongated and flattened, expressed alkaline phosphatase, and eventually mineralized. Type II and X collagen synthesis was halted and replaced by type I collagen synthesis. In addition the cells started to produce and to secrete in large amount a protein with an apparent molecular mass of 82 KD in reducing conditions and 63 KD in unreducing conditions. This protein is soluble in acidic solutions, does not contain collagenous domains, and is glycosylated. The Ch21 protein, a marker of hypertrophic chondrocytes and bone cells, was synthesized throughout the culture. We have defined this additional differentiation stage as an osteoblast-like stage. Calcium deposition in the extracellular matrix occurred regardless of the addition of beta glycerophosphate to the culture medium. Comparable results were obtained both when the cells were plated at low density and when they were already at confluence and maintained in culture without passaging up to 50 d. When retinoic acid was added to the hypertrophic chondrocyte culture between day 1 and day 5 the maturation of the cells to the osteoblast-like stage was highly accelerated. The switch in the collagen secretion was already observed after 2 d and the production of the 63-kD protein after 3 d. Mineralization was observed after 15-20 d.

Cell proliferation, extracellular matrix mineralization, and ovotransferrin transient expression during in vitro differentiation of chick hypertrophic chondrocytes into osteoblast-like cells.

Differentiation of hypertrophic chondrocytes toward an osteoblast-like phenotype occurs in vitro when cells are transferred to anchorage-dependent culture conditions in the presence of ascorbic acid (Descalzi Cancedda, F., C. Gentili, P. Manduca, and R. Cancedda. 1992. J. Cell Biol. 117:427-435). This process is enhanced by retinoic acid addition to the culture medium. Here we compare the growth of hypertrophic chondrocytes undergoing this differentiation process to the growth of hypertrophic chondrocytes maintained in suspension culture as such. The proliferation rate is significantly higher in the adherent hypertrophic chondrocytes differentiating to osteoblast-like cells. In cultures supplemented with retinoic acid the proliferation rate is further increased. In both cases cells stop proliferating when mineralization of the extracellular matrix begins. We also report on the ultrastructural organization of the osteoblast-like cell cultures and we show virtual identity with cultures of osteoblasts grown from bone chips. Cells are embedded in a dense meshwork of type I collagen fibers and mineral is observed in the extracellular matrix associated with collagen fibrils. Differentiating hypertrophic chondrocytes secrete large amounts of an 82-kD glycoprotein. The protein has been purified from conditioned medium and identified as ovotransferrin. It is transiently expressed during the in vitro differentiation of hypertrophic chondrocytes into osteoblast-like cells. In cultured hypertrophic chondrocytes treated with 500 nM retinoic acid, ovotransferrin is maximally expressed 3 d after retinoic acid addition, when the cartilage-bone-specific collagen shift occurs, and decays between the 5th and the 10th day, when cells have fully acquired the osteoblast-like phenotype. Similar results were obtained when retinoic acid was added to the culture at the 50 nM "physiological" concentration. Cells expressing ovotransferrin also coexpress ovotransferrin receptors. This suggests an autocrine mechanism in the control of chondrocyte differentiation to osteoblast-like cells.

Ovotransferrin and ovotransferrin receptor expression during chondrogenesis and endochondral bone formation in developing chick embryo.

Ovotransferrin expression during chick embryo tibia development has been investigated in vivo by immunocytochemistry and in situ hybridization. Ovotransferrin was first observed in the 7 day cartilaginous rudiment. At later stages, the factor was localized in the articular zone of the bone epiphysis and in the bone diaphysis where it was concentrated in hypertrophic cartilage, in zones of cartilage erosion and in the osteoid at the chondro-bone junction. When the localization of the ovotransferrin receptors was investigated, it was observed that chondrocytes at all stages of differentiation express a low level of the oviduct (tissue) specific receptor. Interestingly, high levels of the receptor were detectable in the 13-d old tibia in the diaphysis collar of stacked-osteoprogenitor cells and in the layer of derived osteoblasts. High levels of oviduct receptor were also observed in the primordia of the menisci. Metabolic labeling of proteins secreted by cultured chondrocytes and osteoblasts and Northern blot analysis of RNA extracted from the same cells confirmed and completed the above information. Ovotransferrin was expressed by in vitro differentiating chondrocytes in the early phase of the culture and, at least when culture conditions allowed extracellular matrix assembly, also by hypertrophic chondrocytes and derived osteoblast-like cells. Osteoblasts directly obtained from bone chips produced ovotransferrin only at the time of culture mineralization. By Western blot analysis, oviduct receptor proteins were detected at a very low level in extract from differentiating and hypertrophic chondrocytes and at a higher level in extract from hypertrophic chondrocytes undergoing differentiation to osteoblast-like cells and from mineralizing osteoblasts. Based on these results, the existence of autocrine and paracrine loops involving ovotransferrin and its receptor during chondrogenesis and endochondral bone formation is discussed.

Transferrin promotes endothelial cell migration and invasion: implication in cartilage neovascularization.

During endochondral bone formation, avascular cartilage differentiates to hypertrophic cartilage that then undergoes erosion and vascularization leading to bone deposition. Resting cartilage produces inhibitors of angiogenesis, shifting to production of angiogenic stimulators in hypertrophic cartilage. A major protein synthesized by hypertrophic cartilage both in vivo and in vitro is transferrin. Here we show that transferrin is a major angiogenic molecule released by hypertrophic cartilage. Endothelial cell migration and invasion is stimulated by transferrins from a number of different sources, including hypertrophic cartilage. Checkerboard analysis demonstrates that transferrin is a chemotactic and chemokinetic molecule. Chondrocyte-conditioned media show similar properties. Polyclonal anti-transferrin antibodies completely block endothelial cell migration and invasion induced by purified transferrin and inhibit the activity produced by hypertrophic chondrocytes by 50-70% as compared with controls. Function-blocking mAbs directed against the transferrin receptor similarly reduce the endothelial migratory response. Chondrocytes differentiating in the presence of serum produce transferrin, whereas those that differentiate in the absence of serum do not. Conditioned media from differentiated chondrocytes not producing transferrin have only 30% of the endothelial cell migratory activity of parallel cultures that synthesize transferrin. The angiogenic activity of transferrins was confirmed by in vivo assays on chicken egg chorioallantoic membrane, showing promotion of neovascularization by transferrins purified from different sources including conditioned culture medium. Based on the above results, we suggest that transferrin is a major angiogenic molecule produced by hypertrophic chondrocytes during endochondral bone formation.

Tactile spatial working memory activates the dorsal extrastriate cortical pathway in congenitally blind individuals.

In sighted individuals, both the visual and tactile version of the same spatial working memory task elicited neural responses in the dorsal "where" cortical pathway (Ricciardi et al., 2006). Whether the neural response during the tactile working memory task is due to visually-based spatial imagery or rather reflects a more abstract, supramodal organization of the dorsal cortical pathway remains to be determined. To understand the role of visual experience on the functional organization of the dorsal cortical stream, using functional magnetic resonance imaging (fMRI) here we examined brain response in four individuals with congenital or early blindness and no visual recollection, while they performed the same tactile spatial working memory task, a one-back recognition of 2D and 3D matrices. The blind subjects showed a significant activation in bilateral posterior parietal cortex, dorsolateral and inferior prefrontal areas, precuneus, lateral occipital cortex, and cerebellum. Thus, dorsal occipito-parietal areas are involved in mental imagery dealing with spatial components in subjects without prior visual experience and in response to a non-visual task. These data indicate that recruitment of the dorsal cortical pathway in response to the tactile spatial working memory task is not mediated by visually-based imagery and that visual experience is not a prerequisite for the development of a more abstract functional organization of the dorsal stream. These findings, along with previous data indicating a similar supramodal functional organization within the ventral cortical pathway and the motion processing brain regions, may contribute to explain how individuals who are born deprived of sight are able to interact effectively with the surrounding world.

Spatiotemporal dynamics of single-letter reading: a combined ERP-FMRI study.

This work investigates the neural correlates of single-letter reading by combining event-related potentials (ERPs) and functional magnetic resonance imaging (fMRI), thus exploiting their complementary spatiotemporal resolutions. Three externally-paced reading tasks were administered with an event-related design: passive observation of letters and symbols and active reading aloud of letters. ERP and fMRI data were separately recorded from 8 healthy adults during the same experimental conditions. Due to the presence of artifacts in the EEG signals, two subjects were discarded from further analysis. Independent Component Analysis was applied to ERPs, after dimensionality reduction by Principal Component Analysis: some independent components were clearly related to specific reading functions and the associated current density distributions in the brain were estimated with Low Resolution Electromagnetic Tomography Analysis method (LORETA). The impulse hemodynamic response function was modeled as a linear combination of linear B-spline functions and fMRI statistical analysis was performed by multiple linear regression. fMRI and LORETA maps were superimposed in order to identify the overlapping activations and the activated regions specifically revealed by each modality. The results showed the existence of neuronal networks functionally specific for letter processing and for explicit verbal-motor articulation, including the temporo-parietal and frontal regions. Overlap between fMRI and LORETA results was observed in the inferior temporal-middle occipital gyrus, suggesting that this area has a crucial and multifunctional role for linguistic and reading processes, likely because its spatial location and strong interconnection with the main visual and auditory sensory systems may have favored its specialization in grapheme-phoneme matching.

Neural correlates of spatial working memory in humans: a functional magnetic resonance imaging study comparing visual and tactile processes.

Recent studies of neural correlates of working memory components have identified both low-level perceptual processes and higher-order supramodal mechanisms through which sensory information can be integrated and manipulated. In addition to the primary sensory cortices, working memory relies on a widely distributed neural system of higher-order association areas that includes posterior parietal and occipital areas, and on prefrontal cortex for maintaining and manipulating information. The present study was designed to determine brain patterns of neural response to the same spatial working memory task presented either visually or in a tactile format, and to evaluate the relationship between spatial processing in the visual and tactile sensory modalities. Brain activity during visual and tactile spatial working memory tasks was measured in six young right-handed healthy male volunteers by using functional magnetic resonance imaging. Results indicated that similar fronto-parietal networks were recruited during spatial information processing across the two sensory modalities-specifically the posterior parietal cortex, the dorsolateral prefrontal cortex and the anterior cingulate cortex. These findings provide a neurobiological support to behavioral observations by indicating that common cerebral regions subserve generation of higher order mental representations involved in working memory independently from a specific sensory modality.

Combining electroencephalographic activity and instantaneous heart rate for assessing brain-heart dynamics during visual emotional elicitation in healthy subjects.

Emotion perception, occurring in brain areas such as the prefrontal cortex and amygdala, involves autonomic responses affecting cardiovascular dynamics. However, how such brain-heart dynamics is further modulated by emotional valence (pleasantness/unpleasantness), also considering different arousing levels (the intensity of the emotional stimuli), is still unknown. To this extent, we combined electroencephalographic (EEG) dynamics and instantaneous heart rate estimates to study emotional processing in healthy subjects. Twenty-two healthy volunteers were elicited through affective pictures gathered from the International Affective Picture System. The experimental protocol foresaw 110 pictures, each of which lasted 10 s, associated to 25 different combinations of arousal and valence levels, including neutral elicitations. EEG data were processed using short-time Fourier transforms to obtain time-varying maps of cortical activation, whereas the associated instantaneous cardiovascular dynamics was estimated in the time and frequency domains through inhomogeneous point-process models. Brain-heart linear and nonlinear coupling was estimated through the maximal information coefficient (MIC). Considering EEG oscillations in theθband (4-8 Hz), MIC highlighted significant arousal-dependent changes between positive and negative stimuli, especially occurring at intermediate arousing levels through the prefrontal cortex interplay. Moreover, high arousing elicitations seem to mitigate changes in brain-heart dynamics in response to pleasant/unpleasant visual elicitation.

Brain-heart linear and nonlinear dynamics during visual emotional elicitation in healthy subjects.

This study investigates brain-heart dynamics during visual emotional elicitation in healthy subjects through linear and nonlinear coupling measures of EEG spectrogram and instantaneous heart rate estimates. To this extent, affective pictures including different combinations of arousal and valence levels, gathered from the International Affective Picture System, were administered to twenty-two healthy subjects. Time-varying maps of cortical activation were obtained through EEG spectral analysis, whereas the associated instantaneous heartbeat dynamics was estimated using inhomogeneous point-process linear models. Brain-Heart linear and nonlinear coupling was estimated through the Maximal Information Coefficient (MIC), considering EEG time-varying spectra and point-process estimates defined in the time and frequency domains. As a proof of concept, we here show preliminary results considering EEG oscillations in the θ band (4-8 Hz). This band, indeed, is known in the literature to be involved in emotional processes. MIC highlighted significant arousal-dependent changes, mediated by the prefrontal cortex interplay especially occurring at intermediate arousing levels. Furthermore, lower and higher arousing elicitations were associated to not significant brain-heart coupling changes in response to pleasant/unpleasant elicitations.

Parathyroid hormone activation of map kinase in rat duodenal cells is mediated by 3',5'-cyclic AMP and Ca(2+).

In a previous study, we demonstrated that parathyroid hormone (PTH) stimulates in rat duodenal cells (enterocytes) the phosphorylation and activity of extracellular signal-regulated mitogen-activated protein kinase (MAPK) isoforms ERK1 and ERK2. As PTH activates adenylyl cyclase (AC) and phospholipase C and increases intracellular Ca(2+) in these cells, in the present study we evaluated the involvement of cAMP, Ca(2+) and protein kinase C (PKC) on PTH-induced MAPK activation. We found that MAPK phosphorylation by the hormone did not depend on PKC activation. PTH response could, however, be mimicked by addition of forskolin (5-15 microM), an AC activator, or Sp-cAMP (50-100 microM), a cAMP agonist, and suppressed to a great extent by the AC inhibitor, compound Sq-22536 (0.2-0.4 mM) and the cAMP antagonist Rp-cAMP (0.2 mM). Removal of external Ca(2+) (EGTA 0.5 mM), chelation of intracellular Ca(2+) with BAPTA (5 microM), or blockade of L-type Ca(2+)-channels with verapamil (10 microM) significantly decreased PTH-activation of MAPK. Furthermore, a similar degree of phosphorylation of MAPK was elicited by the Ca(2+) mobilizing agent thapsigargin, the Ca(2+) ionophore A23187, ionomycin and membrane depolarization with high K(+). Inclusion of the calmodulin inhibitor fluphenazine (50 microM) did not prevent hormone effects on MAPK. Taken together, these results indicate that cAMP and Ca(2+) play a role upstream in the signaling mechanism leading to MAPK activation by PTH in rat enterocytes. As Ca(2+) and cAMP antagonists did not block totally PTH-induced MAPK phosphorylation, it is possible that linking of the hormone signal to the MAPK pathway may additionally involve Src, which has been previously shown to be rapidly activated by PTH. Of physiological significance, in agreement with the mitogenic role of the MAPK cascade, PTH increased enterocyte DNA synthesis, and this effect was blocked by the specific inhibitor of MAPK kinase (MEK) PD098059, indicating that hormone modulation of MAPK through these messenger systems stimulates duodenal cell proliferation.

Cholesterol secretion and homeostasis in chondrocytes: a liver X receptor and retinoid X receptor heterodimer mediates apolipoprotein A1 expression.

Cholesterol is required for chondrocyte differentiation and bone formation. Apolipoprotein A1 (apoA-1) plays a major role in lipoprotein clearance and cholesterol redistribution. We report here that apoA-1 is expressed during chondrocyte differentiation in vitro and in vivo. In differentiating chondrocytes, the expression of the liver X receptor (LXR) is modulated and its expression correlates to the expression of apoA-1. The expression of other LXR target genes related to cholesterol homeostasis such as ABCA1 cholesterol transporter and sterol regulatory element-binding protein 1 (SREBP1) is similarly regulated. Small molecule ligands activating either LXR or retinoid X receptor (RXR) lead to a dramatic increase in apoA-1 mRNA and protein expression in cultured chondrocytes. These ligands strongly induce ABCA1 cholesterol transporter expression and effectively mediate cholesterol efflux from hypertrophic chondrocytes. In addition, we report that, in the same cells, the ligands down modulate Serum Amyloid A expression induced by bacterial lipopolysaccharide. Our studies provide evidence that LXR/RXR mediate a fine regulation of cholesterol homeostasis in differentiating chondrocytes.

PTH stimulates PLCbeta and PLCgamma isoenzymes in rat enterocytes: influence of ageing.

We previously reported that in rat duodenal cells (enterocytes), parathyroid hormone (PTH [1-34]: PTH) stimulates the hydrolysis of polyphosphoinositides by phospholipase C (PLC), generating the second messengers inositol trisphosphate (IP(3)) and diacylglycerol (DAG) and that this mechanism is severely altered in old animals. In the present study, we show that PTH [1-34]-dependent IP(3) release in young rats was blocked to a great extent by an antibody against guanine nucleotide binding protein Galphaq/11, indicating that the hormone activates a beta isoform of PLC coupled to the alpha subunit of Gq/11. In addition, PTH rapidly (within 30 s, with maximal effects at 1 min) stimulated tyrosine phosphorylation of PLCgamma in a dose-dependent fashion (10(-10)-10(-7) M). The hormone response was specific as PTH [7-34] was without effects. The tyrosine kinase inhibitors, genistein (100 microM) and herbimycin (2 microM), suppressed PTH-dependent PLCgamma tyrosine phosphorylation. Stimulation of PLCgamma tyrosine phosphorylation by PTH [1-34] greatly decreased with ageing. PP1 (10 microM), a specific inhibitor of the Src family of tyrosine kinases, completely abolished PLCgamma phosphorylation. The hormone-induced Src tyrosine dephosphorylation, a major mechanism of Src activation, an effect that was blunted in old animals. These results indicate that in rat enterocytes PTH generates IP(3) mainly through G-protein-coupled PLCbeta and stimulates PLCgamma phosphorylation via the nonreceptor tyrosine kinase Src. Impairment of PTH activation of both PLC isoforms upon ageing may result in abnormal hormone regulation of cell Ca(2+) and proliferation in the duodenum.