282 research outputs found
A long antisense RNA is transcribed at the 5’ end of the human HIF-1a gene upon drug inhibition of DNA Topoisomerase I.
No full textHypoxia-inducible factor 1 (HIF-1) is a master regulator of the cell response to oxygen deprivation. We have previously shown that the Topoisomerase I (Top1) inhibitor camptothecin (CPT) modifies RNAPII density along transcribed genes suggesting an involvement of Top1 in RNAPII pausing. Here, we demonstrate that CPT affects RNAPII density at the promoter pause site of HIF-1a gene and increases the transcription of specific regions corresponding to the 5’ end of intron 1 in human HCT 116 cells. The effect requires Top1 and is independent of replication-mediated DNA breaks. Chromatin RNA immpunoprecipitation (RIP) experiments show that CPT increases the amount of specific RNA bound to chromatin in a transcription-dependent manner, thus showing that CPT promotes transcription along the studied regions. Further analyses demonstrated that CPT stimulates the transcription of a long RNA, antisense to HIF-1a mRNA, while decreasing HIF-1a mRNA levels. Thus, despite its transcription inhibitory activity, CPT can trigger the production of an antisense transcript at the 5’ end of the HIF 1a gene, likely suggesting a new regulation mechanism of HIF-1a expression and activity
Dissecting the transcriptional functions of human DNA topoisomerase I by selective inhibitors: Implications for physiological and therapeutic modulation of enzyme activity.
No full textCamptothecin is a selective inhibitor of DNA topoisomerase I, and has effective antitumor activity. Recently, camptothecin has been shown to activate the transcription of low-abundance antisense RNAs at the HIF-1alpha gene locus in human cancer cells in a Topoisomerase I-dependent manner. The activation of antisense transcription is likely due to sustained drug interference with transcription regulation mechanisms leading to a more open chromatin conformation and de-repression/activation of antisense transcription. Camptothecin readily inhibits Topoisomerase I in cells, and the enzyme inhibition activates transcriptional Cdk (Cdk9 and/or Cdk7) activity leading to the hyperphosphorylation of the CTD of the largest subunit of RNA polymerase II (RNAP II). This results in an alteration of RNAP II regulation with specific effects at transcription levels. Thus, the findings have documented that camptothecin can interfere with specific transcription regulatory steps, impairing the balance of cellular antisense and sense transcripts at the HIF-1alpha gene locus. That may have a considerable impact on cancer therapy development particularly for non-responsive human tumors
Giovanni Pascoli's 'La grande proletaria si e' mossa': A Translation and Critical Introduction
No full textAt the hundredth anniversary of Italy’s 1911 invasion of Libya, as the effects of European imperialism continue to reverberate in Africa, it seems an especially appropriate time to reconsider the texts that helped shape the discourse of the time and to reflect on the continuing effects that they exert. It is in this context that I present an annotated translation of Giovanni Pascoli’s oration “ La grande proletaria si è mossa.
A New Method for Measuring Bell-Shaped Chest Induced by Impaired Ribcage Muscles in Spinal Muscular Atrophy Children
No full textThe involvement of the respiratory muscular pump makes SMA children prone to frequent hospitalization and morbidity, particularly in type 1. Progressive weakness affects ribcage muscles resulting in bell-shaped chest that was never quantified. The aims of the present work were: (1) to quantify the presence of bell-shaped chest in SMA infants and children and to correlate it with the action of ribcage muscles, assessed by the contribution of pulmonary ribcage to tidal volume (Delta V-RC,V- p); (2) to verify if and how the structure of the ribcage and Delta V-RC,V- p change after 1-year in SMA type 2. 91 SMA children were studied in supine position during awake spontaneous breathing: 32 with type 1 (SMA1, median age: 0.8 years), 51 with type 2 (SMA2, 3.7 years), 8 with type 3 (SMA3, 5.4 years) and 20 healthy children (HC, 5.2 years). 14 SMA2 showed negative Delta V-RC,V- p (SMA2px), index of paradoxical inspiratory inward motion. The bell-shaped chest index was defined as the ratio between the distance of the two anterior axillary lines at sternal angle and the distance between the right and left 10th costal cartilage. If this index was > 1 an inverted triangle shape was identified. While the bell-shaped index was similar between HC (0.92) and SMA3 (0.91), it was significantly (p < 0.05) reduced in SMA2 (0.81), SMA2px (0.74) and SMA1 (0.73), being similar between the last two. There was a good correlation (Spearman's rank correlation coefficient, rho = 0.635, p < 0.001) between ribcage geometry and Delta V-RC, (p). After 1 year, Delta V-RC,V- p reduced while bell-shaped chest index did not change being significantly lower than HC. The shape of the ribcage was quantified and correlated with the action of ribcage muscles in SMA children. The impaired ribcage muscles function alters the ribcage structure. HC and SMA3 show an almost rectangular ribcage shape, whereas SMA2, SMA2px and SMA1 are characterized by bell-shaped chest. In SMA, therefore, a vicious cycle starts since infancy: the disease progressively affects ribcage muscles resulting in reduced expansion of lung and ribcage that ultimately alters ribcage shape. This puts the respiratory muscles at mechanical disadvantage
The neurological examination of the newborn baby
No full textThis paper provides an overview of the value of a structured neonatal neurological examination that may be performed in different settings, from routine examination to research settings. We will report how a structured neurological examination can help to identify infants with central and peripheral nervous system involvement. We also describe a short but structured proforma to be used for the routine examination of full-term infants. We will finally describe a quantitative assessment to be used in research settings
Interleukin-21 (IL-21) synergizes with IL-2 to enhance T-cell receptor-induced human T-cell proliferation and counteracts IL-2/transforming growth factor-beta-induced regulatory T-cell development
No full textInterleukin-2 (IL-2) is a mainstay for current immunotherapeutic protocols but its usefulness in patients is reduced by severe toxicities and because IL-2 facilitates regulatory T (Treg) cell development. IL-21 is a type I cytokine acting as a potent T-cell co-mitogen but less efficient than IL-2 in sustaining T-cell proliferation. Using various in vitro models for T-cell receptor (TCR)-dependent human T-cell proliferation, we found that IL-21 synergized with IL-2 to make CD4(+) and CD8(+) T cells attain a level of expansion that was impossible to obtain with IL-2 alone. Synergy was mostly evident in naive CD4(+) cells. IL-2 and tumour-released transforming growth factor-β (TGF-β) are the main environmental cues that cooperate in Treg cell induction in tumour patients. Interleukin-21 hampered Treg cell expansion induced by IL-2/TGF-β combination in naive CD4(+) cells by facilitating non-Treg over Treg cell proliferation from the early phases of cell activation. Conversely, IL-21 did not modulate the conversion of naive activated CD4(+) cells into Treg cells in the absence of cell division. Treg cell reduction was related to persistent activation of Stat3, a negative regulator of Treg cells associated with down-modulation of IL-2/TGF-β-induced phosphorylation of Smad2/3, a positive regulator of Treg cells. In contrast to previous studies, IL-21 was completely ineffective in counteracting the suppressive activity of Treg cells on naive and memory, CD4(+) and CD8(+) T cells. Present data provide proof-of-concept for evaluating a combinatorial approach that would reduce the IL-2 needed to sustain T-cell proliferation efficiently, thereby reducing toxicity and controlling a tolerizing mechanism responsible for the contraction of the T-cell response
Development of an International SMA Bulbar Assessment for Inter-professional Administration
No full textBackground:
Progressive weakness can affect bulbar muscles in individuals with moderate to severe forms of spinal muscular atrophy (SMA). The paucity of standardized, valid bulbar assessments capturing clinically significant deficits in SMA impedes the ability to monitor function, facilitate intervention, or detect treatment response.
Objective:
To fill this void, an international multidisciplinary team gathered to develop an agreed upon consensus-derived assessment of bulbar function in SMA for inter-professional administration to enhance our ability to monitor disease progression, support clinical management, and evaluate treatment effects.
Methods:
Fifty-six international clinicians experienced in SMA were invited and engaged using the Delphi method over multiple rounds of web-based surveys to establish consensus.
Results:
Serial virtual meetings occurred with 42 clinicians (21 speech and language therapists, 11 physical therapists, 5 neurologists, 4 occupational therapists, and 1 dentist). Seventy-two validated assessments of bulbar function were identified for potential relevance to individuals with SMA (32 accessible objective, 11 inaccessible objective, 29 patient-reported outcomes). Delphi survey rounds (n = 11, 15, 15) achieved consensus on individual items with relevance and wording discussed. Key aspects of bulbar function identified included: oral intake status, oral facial structure and motor strength, swallowing physiology, voice & speech, and fatigability.
Conclusions:
Multidisciplinary clinicians with expertise in bulbar function and SMA used Delphi methodology to reach consensus on assessments/items considered relevant for SMA across all age groups. Future steps include piloting the new scale moving towards validation/reliability. This work supports the advancement of assessing bulbar function in children and adults with SMA by a variety of professionals
Induction of a novel long antisense RNA from the human HIF-1a locus may contribuite to HIF 1a regulation and inhibition by campotecin in cancer cells.
No full textAbstract # 375
Transcriptional Stress by Camptothecin: Mechanisms and Implications for the Drug Antitumor Activity
No full textThe cell killing activity of antitumor camptothecins is due to collisions between drug-trapped Topoisomerase I (Top1) and DNA replication forks, leading to irreversible DNA double-strand breaks and apoptosis. In addition, recent evidences demonstrated that camptothecins have specific transcription-dependent effects that are independent from DNA breaks at replication forks. Here, we focus on the latter drug effects, discussing the influence of Top1 and camptothecins on RNA polymerase II regulation by cyclin-dependent kinases, co-transcriptional regulation of mRNA maturation, and activation of novel antisense RNAs at the human HIF-1α gene locus. The new findings suggest that specific transcription-dependent effects of the drug can contribute to the antitumor activity of camptothecins and upcoming non-camptothecin Top1-targeted drugs. The complete understanding of specific regulatory mechanisms altered by camptothecins may lead to the definition of useful novel targets for human tumor therapy
External hydrocephalus in discordant birth weight twins: a case report
No full textThe term "external hydrocephalus (EH)" is used to describe excessively rapid head growth in infants who are found to have enlarged subarachnoid spaces and little or no ventricular enlargement. EH has not yet been described in discordant birth weight twins. We report the cases of two sets of discordant twins with normal neonatal course and normal neonatal brain ultrasound scans who developed an EH in the first months after birth and had a mild neurodevelopmental delay. Our findings suggest that EH may be part of neurologic morbidity in discordant birth weight twins and represents one of the potential complications to look for in the follow-up of these infants
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