Galectin-3. One molecule for an alphabet of diseases, from A to Z

Galectin-3 (Gal-3) regulates basic cellular functions such as cell–cell and cell–matrix interactions, growth, proliferation, differentiation, and inflammation. It is not surprising, therefore, that this protein is involved in the pathogenesis of many relevant human diseases, including cancer, fibrosis, chronic inflammation and scarring affecting many different tissues. The papers published in the literature have progressively increased in number during the last decades, testifying the great interest given to this protein by numerous researchers involved in many different clinical contexts. Considering the crucial role exerted by Gal-3 in many different clinical conditions, Gal-3 is emerging as a new diagnostic, prognostic biomarker and as a new promising therapeutic target. The current review aims to extensively examine the studies published so far on the role of Gal-3 in all the clinical conditions and diseases, listed in alphabetical order, where it was analyzed

NF-Y Dependent Epigenetic Modifications Discriminate between Proliferating and Postmitotic Tissue

The regulation of gene transcription requires posttranslational modifications of histones that, in concert with chromatin remodeling factors, shape the structure of chromatin. It is currently under intense investigation how this structure is modulated, in particular in the context of proliferation and differentiation. Compelling evidence suggests that the transcription factor NF-Y acts as a master regulator of cell cycle progression, activating the transcription of many cell cycle regulatory genes. However, the underlying molecular mechanisms are not yet completely understood. Here we show that NF-Y exerts its effect on transcription through the modulation of the histone “code”. NF-Y colocalizes with nascent RNA, while RNA polymerase II is I phosphorylated on serine 2 of the YSPTSPS repeats within its carboxyterminal domain and histones are carrying modifications that represent activation signals of gene expression (H3K9ac and PAN-H4ac). Comparing postmitotic muscle tissue from normal mice and proliferating muscles from mdx mice, we demonstrate by chromatin immunoprecipitation (ChIP) that NF-Y DNA binding activity correlates with the accumulation of acetylated histones H3 and H4 on promoters of key cell cycle regulatory genes, and with their active transcription. Accordingly, p300 is recruited onto the chromatin of NF-Y target genes in a NF-Y-dependent manner, as demonstrated by Re-ChIP. Conversely, the loss of NF-Y binding correlates with a decrease of acetylated histones, the recruitment of HDAC1, and a repressed heterochromatic state with enrichment of histones carrying modifications known to mediate silencing of gene expression (H3K9me3, H3K27me2 and H4K20me3). As a consequence, NF-Y target genes are downregulated in this context. In conclusion, our data indicate a role of NF-Y in modulating the structure and transcriptional competence of chromatin in vivo and support a model in which NF-Y-dependent histone “code” changes contribute to the proper discrimination between proliferating and postmitotic cells in vivo and in vitro

Thyroid hormones regulate cardiac repolarization and QT-interval related gene expression in hiPSC cardiomyocytes

Prolongation of cardiac repolarization (QT interval) represents a dangerous and potentially life-threatening electrical event affecting the heart. Thyroid hormones (THs) are critical for cardiac development and heart function. However, little is known about THs influence on ventricular repolarization and controversial effects on QT prolongation are reported. Human iPSC-derived cardiomyocytes (hiPSC-CMs) and multielectrode array (MEA) systems were used to investigate the influence of 3,3',5-triiodo-L-Thyronine (T3) and 3,3',5,5'-tetraiodo-L-Thyronine (T4) on corrected Field Potential Duration (FPDc), the in vitro analog of QT interval, and on local extracellular Action Potential Duration (APD). Treatment with high THs doses induces a significant prolongation of both FPDc and APD, with the strongest increase reached after 24 h exposure. Preincubation with reverse T3 (rT3), a specific antagonist for nuclear TH receptor binding, significantly reduces T3 effects on FPDc, suggesting a TRs-mediated transcriptional mechanism. RNA-seq analysis showed significant deregulation in genes involved in cardiac repolarization pathways, including several QT-interval related genes. In conclusion, long-time administration of high THs doses induces FPDc prolongation in hiPSC-CMs probably through the modulation of genes linked to QT-interval regulation. These results open the way to investigate new potential diagnostic biomarkers and specific targeted therapies for cardiac repolarization dysfunctions

CDKL5 localizes at the centrosome and midbody and is required for faithful cell division

The cyclin-dependent kinase-like 5 (CDKL5) gene has been associated with rare neurodevelopmental disorders characterized by the early onset of seizures and intellectual disability. The CDKL5 protein is widely expressed in most tissues and cells with both nuclear and cytoplasmic localization. In post-mitotic neurons CDKL5 is mainly involved in dendritic arborization, axon outgrowth, and spine formation while in proliferating cells its function is still largely unknown. Here, we report that CDKL5 localizes at the centrosome and at the midbody in proliferating cells. Acute inactivation of CDKL5 by RNA interference (RNAi) leads to multipolar spindle formation, cytokinesis failure and centrosome accumulation. At the molecular level, we observed that, among the several midbody components we analyzed, midbodies of CDKL5-depleted cells were devoid of HIPK2 and its cytokinesis target, the extrachromosomal histone H2B phosphorylated at S14. Of relevance, expression of the phosphomimetic mutant H2B-S14D, which is capable of overcoming cytokinesis failure in HIPK2-defective cells, was sufficient to rescue spindle multipolarity in CDKL5-depleted cells. Taken together, these results highlight a hitherto unknown role of CDKL5 in regulating faithful cell division by guaranteeing proper HIPK2/H2B functions at the midbody

NF-Y recruits p300 onto its target promoters.

<p>(A) Cells were immunosteined with anti-NF-YA (ii, vii), anti-p300 (i), anti-HDAC1 (v) antibodies. Panels iii and vii show the overlay of two proteins, panels iv and viii represents a typical optical field of merge. Confocal analysis of single optical section is shown. (B) ChIPs and re-ChIPs experiments performed with anti-NF-YA, -NF-YB and –p300 antibodies, on proliferating C2C12 cells and stable transfected C2C12 with pmut-CCAATcyclinB2-LUC vector. PCR analysis were performed on the immunoprecipitated DNA samples using specific primers for the indicated promoters and specific primers for the exogenous cyclin B2 mutated promoter. No antibody was used as control (No Ab). (C) Q-Re-ChIP analysis performed on proliferating (P) and terminally differentiated (TD) C2C12 cells using the indicated antibodies on the sames promoters of panel B. (D) Q-ChIP experiments performed with anti-NF-YA, –p300 antibodies, using chromatin prepared from adductor muscles of wt (white bars) and mdx (black bars) of C57BL/10 mice. Specific primers for <i>Cdk1, Cyclin A2, Cyclin B2</i> and <i>MLC</i> promoters. The values represent the mean of five indipendent experiments performed on triplicate.</p

Histone acetylation correlates with NF-Y recruitment onto its target promoters.

<p>(A) ChIPs performed on proliferating (P) and terminally differentiated (TD) C2C12 cells using the indicated antibodies. No antibody was used as control (No Ab). (B) Q-ChIP analysis on proliferating (P) and terminally differentiated (TD) primary myoblasts, performed with the indicated antibodies. The promoters analyzed were: 1) <i>CyclinA2,</i> 2) <i>CyclinB1</i>, 3) <i>CyclinB2,</i> 4) <i>Cdk1</i>, 5) <i>Cdc25C,</i> 6) <i>Dhfr,</i> 7) <i>TopoisomeraseIIα,</i> 8) <i>Tk.</i> (C) Q-ChIP analysis of the <i>Myogenin</i> and <i>MLC</i> promoters performed with the indicated antibodies on proliferating (P) and terminally differentiated (TD) primary myoblasts. On B and C the enrichment of immunoprecipitated promoter fragments relative to the input was done. Rabbit IgG was used as control. (D) RT-PCR amplification of indicated genes was performed on proliferating (P) and terminal differentiated (TD) C2C12.</p

Model proposing the molecular mechanism underlying the transcriptional control of cell cycle-related genes by NF-Y.

<p>Model proposing the molecular mechanism underlying the transcriptional control of cell cycle-related genes by NF-Y.</p