Vittoria Carnicelli

Cardiac effects of 3-iodothyronamine: a new aminergic system modulating cardiac function

3‐iodothyronamine T1AM is a novel endogenous thyroid hormone derivative that activates the G protein‐coupled receptor known as trace anime‐associated receptor 1 (TAAR1). In the isolated working rat heart and in rat cardiomyocytes, T1AM produced a reversible, dose‐dependent negative inotropic effect (e.g.,27±5, 51 ±3, and 65±2% decrease in cardiac output at 19, 25, and 38 μM concentration, respectively). An independent negative chronotropic effect was also observed. The hemodynamic effects of T1AM were remarkably increased in the presence of the tyrosine kinase inhibitor genistein, whereas they were attenuated in the presence of the tyrosine phosphatase inhibitor vanadate. No effect was produced by inhibitors of protein kinase A, protein kinase C, calcium‐calmodulin kinase II, phosphatidylinositol‐3‐kinase, or MAP kinases. Tissue cAMP levels were unchanged. In rat ventricular tissue, Western blot experiments with antiphosphotyrosine antibodies showed reduced phosphorylation of microsomal and cytosolic proteins after perfusion with synthetic T1AM;reverse transcriptase‐polymerase chain reaction experiments revealed the presence of transcripts for at least 5 TAAR subtypes; specific and saturable binding of [125I]T1AM was observed, with a dissociation constant in the low micromolar range (5 μM); and endogenous T1AM was detectable by tandem mass spectrometry. In conclusion, our findings provide evidence for the existence of a novel aminergic system modulating cardiac function.—Chiellini G., Frascarelli, S., Ghelardoni, S., Carnicelli, V., Tobias, S. C., DeBarber, A., Brogioni, S., Ronca‐Testoni, S., Cerbai, E., Grandy, D. K., Scanlan, T. S., Zucchi R. Cardiac effects of 3‐iodothyronamine: a new aminergic system modulating cardiac function. FASEB J. 21, 1597–1608 (2007)

Ghrelin tissue distribution: comparison between gene and protein expression

Ghrelin, the natural ligand of the GH secretagogue (GHS) receptor, was originally isolated from the stomach and detected in several tissues, but a systematic study of its tissue distribution has not been performed. In the present investigation, we evaluated ghrelin gene expression (by RT-PCR technique) and ghrelin protein concentration (by enzyme immunoassay technique) in tissues obtained from control rats as well as in rats subjected to 48-h fasting. The ghrelin gene was expressed in stomach, small intestine, brain, cerebellum, pituitary, heart, pancreas, salivary gland, adrenal, ovary and testis, with maximum expression occurring in the stomach, while no significant expression was detected by standard RT-PCR in liver, lung, kidney and skeletal muscle. Ghrelin protein was detected in stomach, small intestine, brain, cerebellum, pituitary, lung, skeletal muscle pancreas, salivary gland, adrenal, ovary and testis, at concentrations ranging from 0.05 to 1.43 ng/mg of homogenate protein (the highest concentration occurred in the lung, followed by the brain). Ghrelin was not detectable in the heart, liver and kidney. Therefore, gene and protein expression were dissociated. Fasting did not produce significant changes in ghrelin gene expression, while the distribution of ghrelin between different tissues was significantly modified: protein concentration increased in the brain, cerebellum, lung and salivary gland, while it decreased in the stomach.

FHIT and p53 gene abnormalities in bronchioloalveolar carcinomas. Correlations with clinicopathological data and K-ras mutations

Bronchioloalveolar carcinoma (BAC) is a particular type of adenocarcinoma of the lung which accounts for up to 9 per cent of pulmonary malignancies. The aetiology and pathogenesis of this unique neoplastic disease are still unclear. Three histological subtypes of BAC have been recognized: mucinous, non‐mucinous, and sclerosing. Of these, mucinous and sclerosing BAC have a worse prognosis than non‐mucinous tumours. The different morphological patterns and clinical outcomes of the subtypes of BAC suggest differences in their biological behaviour. Previous reports have shown that the mucinous form of BAC is characterized by constant mutations at codon 12 of the K‐ras gene, whereas the other two histotypes show a frequency of K‐ras mutations which is not different from that observed in conventional lung adenocarcinomas. The present study of a series of 51 BACs, previously investigated for K‐ras gene mutations, has evaluated the status of two other genes, p53 and FHIT, known to be frequently altered in non‐small cell lung cancer. Loss of heterozygosity at microsatellite‐containing loci located within the FHIT gene was observed in 22 (43 per cent) BACs. The distribution of FHIT gene abnormalities was not statistically different in the three histological subtypes. p53 mutations were present in 13 (32 per cent) non‐mucinous/sclerosing BACs, while no mutations were seen in mucinous tumours (P‐0·039). Correlations with clinicopathological parameters showed that p53 mutations in BACs are associated with more aggressive tumours. No correlations were observed between FHIT or K‐ras gene abnormalities and clinicopathological data. In conclusion, these results indicate that FHIT alterations are frequently involved in BAC tumourigenesis and that genetic changes in the p53 and K‐ras genes can distinguish between different histotypes of BAC.

Constitutive Expression of Pluripotency-Associated Genes in Mesodermal Progenitor Cells (MPCs)

Background We recently characterized a progenitor of mesodermal lineage (MPCs) from the human bone marrow of adults or umbilical cord blood. These cells are progenitors able to differentiate toward mesenchymal, endothelial and cardiomyogenic lineages. Here we present an extensive molecular characterization of MPCs, from bone marrow samples, including 39 genes involved in stem cell machinery, differentiation and cell cycle regulation. Methodology/Principal Findings MPCs are cytofluorimetrically characterized and quantitative RT-PCR was performed to evaluate the gene expression profile, comparing it with MSCs and hESCs lines. Immunofluorescence and dot-blot analysis confirm qRT-PCR data. MPCs exhibit an increased expression of OCT4, NANOG, SALL4, FBX15, SPP1 and to a lesser extent c-MYC and KLF4, but lack LIN28 and SOX2. MPCs highly express SOX15. Conclusions/Significance MPCs express many pluripotency-associated genes and show a peculiar Oct-4 molecular circuit. Understanding this unique molecular mechanism could lead to identifying MPCs as feasible, long telomeres, target cells for reprogramming with no up-regulation of the p53 pathway. Furthermore MPCs are easily and inexpensively harvested from human bone marrow.

Distribution of exogenous [125I]-3-iodothyronamine in mouse in vivo: relationship with trace amine-associated receptors

3-Iodothyronamine (T1AM) is a novel chemical messenger, structurally related to thyroid hormone, able to interact with G protein-coupled receptors known as trace amine-associated receptors (TAARs). Little is known about the physiological role of T1AM. In this prospective, we synthesized [125I]-T1AM and explored its distribution in mouse after injecting in the tail vein at a physiological concentration (0.3 nM). The expression of the nine TAAR subtypes was evaluated by quantitative real-time PCR. [125I]-T1AM was taken up by each organ. A significant increase in tissue vs blood concentration occurred in gallbladder, stomach, intestine, liver, and kidney. Tissue radioactivity decreased exponentially over time, consistent with biliary and urinary excretion, and after 24 h, 75% of the residual radioactivity was detected in liver, muscle, and adipose tissue. TAARs were expressed only at trace amounts in most of the tissues, the exceptions being TAAR1 in stomach and testis and TAAR8 in intestine, spleen, and testis. Thus, while T1AM has a systemic distribution, TAARs are only expressed in certain tissues suggesting that other high-affinity molecular targets besides TAARs exist.

Alterations of P16 (MTS1) in node-positive non-small cell lung carcinomas

The status of the P16 gene was investigated by Southern blot, polymerase chain reaction–single strand conformational polymorphism (PCR–SSCP), and DNA sequencing analyses in 30 primary resected non‐small cell lung carcinomas (NSCLCs) with metastatic involvement of thoracic lymph nodes and 33 NSCLCs without node metastases. Direct sequencing of tumour DNA samples scored positive by PCR–SSCP showed five somatic mutations of the P16 gene: four nonsense and one frameshift. The Southern blot analysis revealed the presence of a homozygous deletion of the P16 locus in one tumour. All of the six NSCLCs with somatic aberrations of the P16 gene belonged to the series of tumours with metastatic diffusion to thoracic lymph nodes. In each of these six cases, the genetic aberration was seen in both the primary tumour and the node metastasis. No P16 alteration was found in tumours without metastatic lymph nodes. This difference was statistically significant (P=0·02). No correlation was present between P16 alterations and other clinicopathological parameters including age of patients, tumour size, histological type, and grade. In three tumours with genetic aberration of P16, there was a concomitant alteration of the p53 gene. Our results indicate that the P16 gene is infrequently mutated (10 per cent of the cases examined) in primary resected NSCLC. However, since P16 mutations were found only in metastatic tumours, they may be important events in late phases of tumour progression and could represent useful markers of tumour aggressiveness in NSCLC.

Mesodermal Progenitor Cells (MPCs) Differentiate into Mesenchymal Stromal Cells (MSCs) by Activation of Wnt5/Calmodulin Signalling Pathway

Background Mesenchymal Stromal Cells (MSCs) remain poorly characterized because of the absence of manifest physical, phenotypic, and functional properties in cultured cell populations. Despite considerable research on MSCs and their clinical application, the biology of these cells is not fully clarified and data on signalling activation during mesenchymal differentiation and proliferation are controversial. The role of Wnt pathways is still debated, partly due to culture heterogeneity and methodological inconsistencies. Recently, we described a new bone marrow cell population isolated from MSC cultures that we named Mesodermal Progenitor Cells (MPCs) for their mesenchymal and endothelial differentiation potential. An optimized culture method allowed the isolation from human adult bone marrow of a highly pure population of MPCs (more than 97%), that showed the distinctive SSEA-4+CD105+CD90neg phenotype and not expressing MSCA-1 antigen. Under these selective culture conditions the percentage of MSCs (SSEA-4negCD105+CD90bright and MSCA-1+), in the primary cultures, resulted lower than 2%. Methodology/Principal Finding We demonstrate that MPCs differentiate to MSCs through an SSEA-4+CD105+CD90bright early intermediate precursor. Differentiation paralleled the activation of Wnt5/Calmodulin signalling by autocrine/paracrine intense secretion of Wnt5a and Wnt5b (p<0.05 vs uncondictioned media), which was later silenced in late MSCs (SSEA-4neg). We found the inhibition of this pathway by calmidazolium chloride specifically blocked mesenchymal induction (ID50 = 0.5 µM, p<0.01), while endothelial differentiation was unaffected. Conclusion The present study describes two different putative progenitors (early and late MSCs) that, together with already described MPCs, could be co-isolated and expanded in different percentages depending on the culture conditions. These results suggest that some modifications to the widely accepted MSC nomenclature are required.

Ca2+ channel remodeling in perfused heart: effects of mechanical work and interventions affecting Ca2+ cycling on sarcolemmal and sarcoplasmic reticulum Ca2+ channels

We investigated whether changes in cardiac work or in Ca2+ fluxes may affect the expression of sarcolemmal or sarcoplasmic reticulum Ca2+ channels (DHPRs and RyRs, respectively). Isolated rat hearts were perfused at low Ca2+ concentration (0.8 mM instead of 1.5 mM), at low preload (5 cm instead of 20 cm), in the presence of 100 nM nifedipine or with a cardioplegic solution. After 60 min, hypocalcemic perfusion produced significant reduction in [3H]‐PN 200–110 and [3H]‐ryanodine binding, due to ≈30% reduction in Bmax (P<0.01), with unchanged Kd. Such modifications were reversible. Similar results were obtained in the nifedipine and cardioplegia groups. Low preload perfusion produced similar contractile effects as hypocalcemic perfusion, but it had no effect on radioligand binding. After hypocalcemic perfusion, DHPR and RyR gene expression, evaluated by RT‐PCR, were not modified. Chelerythrine (protein kinase C inhibitor) and lavendustin C (Ca2+/calmodulin‐dependent protein kinase II inhibitor), but not H‐89 (protein kinase A inhibitor), abolished the effects of hypocalcemic perfusion on [3H]‐PN 200–110 and [3H]‐ryanodine binding. We conclude that reduced Ca2+ entry and/or intracellular Ca2+ cycling determines DHPR and RyR remodeling through posttranslational protein modifications. Both protein kinase C and Ca2+/calmodulin‐dependent protein kinase II appear to play a role in this phenomenon.

Plasticity of human dental pulp stromal cells with bioengineering platforms: A versatile tool for regenerative medicine.

In recent years, human dental pulp stromal cells (DPSCs) have received growing attention due to their characteristics in common with other mesenchymal stem cells, in addition to the ease with which they can be harvested. In this study, we demonstrated that the isolation of DPSCs from third molar teeth of healthy individuals allowed the recovery of dental mesenchymal stem cells that showed self-renewal and multipotent differentiation capability. DPSCs resulted positive for CD73, CD90, CD105, STRO-1, negative for CD34, CD45, CD14 and were able to differentiate into osteogenic and chondrogenic cells. We also assayed the angiogenic potential of DPSCs, their capillary tube-like formation was assessed using an in vitro angiogenesis assay and the uptake of acetylated low-density lipoprotein was measured as a marker of endothelial function. Based on these results, DPSCs were capable of differentiating into cells with phenotypic and functional features of endothelial cells. Furthermore, this study investigated the growth and differentiation of human DPSCs under a variety of bioengineering platforms, such as low frequency ultrasounds, tissue engineering and nanomaterials. DPSCs showed an enhanced chondrogenic differentiation under ultrasound application. Moreover, DPSCs were tested on different scaffolds, poly(vinyl alcohol)/gelatin (PVA/G) sponges and human plasma clots. We showed that both PVA/G and human plasma clot are suitable scaffolds for adhesion, growth and differentiation of DPSCs toward osteoblastic lineages. Finally, we evaluated the interactions of DPSCs with a novel class of nanomaterials, namely boron nitride nanotubes (BNNTs). From our investigation, DPSCs have appeared as a highly versatile cellular tool to be employed in regenerative medicine.

ETA receptor-mediated Ca2+ mobilisation in H9c2 cardiac cells

Expression and pharmacological properties of endothelin receptors (ETRs) were investigated in H9c2 cardiomyoblasts. The mechanism of receptor-mediated modulation of intracellular Ca(2+) concentration ([Ca(2+)](i)) was examined by measuring fluorescence increase of Fluo-3-loaded cells with flow cytometry. Binding assays showed that [125I]endothelin-1 (ET-1) bound to a single class of high affinity binding sites in cardiomyoblast membranes. Endothelin-3 (ET-3) displaced bound [125I]ET-1 in a biphasic manner, in contrast to an ET(B)-selective agonist, IRL-1620, that was ineffective. The ET(B)-selective antagonist, BQ-788, inhibited [125I]ET-1 binding in a monophasic manner and with low potency. An ET(A)-selective antagonist, BQ-123, competed [125I]ET-1 binding in a monophasic manner. This antagonist was found to be 13-fold more potent than BQ-788. Immunoblotting analysis using anti-ET(A) and -ET(B) antibodies confirmed a predominant expression of the ET(A) receptor. ET-1 induced a concentration-dependent increase of Fluo-3 fluorescence in cardiomyoblasts resuspended in buffer containing 1mM CaCl(2). Treatment of cells with antagonists, PD-145065 and BQ-123, or a phospholipase C-beta inhibitor, U-73122, abolished ET-1-mediated increases in fluorescence. The close structural analogue of U-73122, U-73343, caused a minimal effect on the concentration-response curve of ET-1. ET-3 produced no major increase of Fluo-3 fluorescence. Removal of extracellular Ca(2+) resulted in a shift to the right of the ET-1 concentration-response curve. Both the L-type voltage-operated Ca(2+) channel blocker, nifedipine, and the ryanodine receptor inhibitor, dantrolene, reduced the efficacy of ET-1. Two protein kinase C inhibitors reduced both potency and efficacy of ET-1. Our results demonstrate that ET(A) receptors are expressed and functionally coupled to rise of [Ca(2+)](i) in H9c2 cardiomyoblasts. ET-1-induced [Ca(2+)](i) increase is triggered by Ca(2+) release from intracellular inositol 1,4,5-trisphosphate-gated stores; plasma membrane Ca(2+) channels and ryanodine receptors participate in sustaining the Ca(2+) response. Regulation of channel opening by protein kinase C is also involved in the process of [Ca(2+)](i) increase.