Transduction signals induced in rat brain cortex astrocytes by the HIV-1 gp120 glycoprotein

AbstractCultures of rat brain cortex astrocytes were exposed to 10−10−10−9 M of the HIV-1 envelope glycoprotein, gp120. No specific binding was revealed by the iodinated protein, suggesting expression of only a few sites onto the cells. In contrast, two transduction signals were rapidly induced by gp120: increased tyrosine phosphorylation of a ∼56 kDa protein and increased [Ca2+]i. This latter effect, present in 13 of the investigated astrocytes, consisted in: discrete or biphasic peaks; slowly rising plateaus; and various types of oscillations. Moreover, in apparently unresponsive cells [Ca2+]i rose slowly (45 min) to double the resting levels. Rat brain cortex astrocytes thus appear highly sensitive to gp120. The induced array of signals might contribute to neurotoxicity during HIV infection

Overall Lack of Regulated Secretion in a PC12 Variant Cell Clone

Abstract A stable clone of PC12 neuroendocrine cells, named 27, known from previous studies to exhibit a defect of regulated secretion (lack of regulated secretory proteins, of synaptophysin, of dense granules and of catecholamine uptake and release; Clementi, E., Racchetti, G., Zacchetti, D., Panzeri, M. C., and Meldolesi, J. (1992) Eur. J. Neurosci. 4, 944-953) was characterized in detail to clarify the nature of its phenotype and the mechanisms of its establishment. The neuroendocrine nature of the PC12-27 phenotype was documented by specific markers: synapsins, neurofilament subunit H, neuronal kinesin, and α-latrotoxin receptor. Moreover, various intracellular membrane systems of PC12-27, including the endoplasmic reticulum and the Golgi complex, appeared similar to control PC12 in both morphology and marker expression. In contrast, all the investigated markers located either in dense granules (dopamine-β-hydroxylase), in synaptic-like microvesicles (the acetylcholine transporter) or in both these regulated secretory organelles (VAMP2/synaptobrevin-2, synaptotagmin) were missing in PC12-27 cells, and the same was true also for the cytosolic and plasmalemma proteins involved in regulated exocytosis (Rab3, SNAP25, syntaxin). Pulse labeling and in vitro translation experiments revealed the defect to consist in a protein synthesis blockade that mRNA studies (reverse transcription-polymerase chain reaction, Northern blotting, and actinomycin D experiments) revealed to take place primarily at the transcriptional level. The secretion defect of PC12-27 cells was modified neither by various types of long term stimulation nor by nerve growth factor treatment. Moreover, when one of the missing regulated secretory proteins, chromogranin B, was expressed by cDNA transfection, it was secreted, however via the constitutive pathway. Our results demonstrate that PC12-27 cells are fully incompetent for both branches of regulated secretion, those of dense granules and synaptic-like microvesicles, possibly because of the impairment of a general expression control system that appears to operate independently of neuroendocrine cell differentiation

Predictive and prognostic value of inflammatory markers in locally advanced rectal cancer (PILLAR) – A multicentric analysis by the Italian Association of Radiotherapy and Clinical Oncology (AIRO) Gastrointestinal Study Group

Background: Patients (pts) affected with locally advanced rectal cancer (LARC) may respond differently to neoadjuvant chemoradiotherapy (nCRT). The identification of reliable biomarkers able to predict oncological outcomes could help in the development of risk-adapted treatment strategies. It has been suggested that inflammation parameters may have a role in predicting tumor response to nCRT and survival outcomes and in rectal cancer, but no definitive conclusion can be drawn at present. The aim of the current study is to evaluate the role of baseline inflammatory markers as prognostic and predictive factors in a large multicentric Italian cohort of LARC pts. Methods: Patients diagnosed with LARC from January 2002 to December 2019 in 9 Italian centers were retrospectively collected. Patients underwent long-course RT with chemotherapy based on fluoropyrimidine ± oxaliplatin followed by surgery. Inflammatory markers were retrieved based on a pre-treatment blood sample including HEI (hemo-eosinophils inflammation index), SII (systemic index of inflammation), NLR (neutrophil-to-lymphocyte ratio), PLR (platelet-to-lymphocyte ratio) and MLR (monocyte-to-lymphocyte ratio). Outcomes of interest were pathological complete response (pCR), disease-free survival (DFS), and overall survival (OS). Results: 808 pts were analyzed. pCR rate was 22 %, 5yOS and 5yDFS were 84.0% and 63.1% respectively. Multivariate analysis identified that a NLR cut-off value >1.2 and SII cut-off value >500 could predict pCR (p = 0.05 and 0.009 respectively). In addition to age, extramesorectal nodes and RT dose, MLR >0.18 (p = 0.03) and HEI = 3 (p = 0.05) were independent prognostic factors for DFS. Finally, age, RT dose, MLR with a cut-off >0.35 (p = 0.028) and HEI = 3 (p = 0.045) were independent predictors of OS. Conclusions: Higher values of baseline composite inflammatory markers can serve as predictors of lower pCR rates and worse survival outcomes in LARC patients undergoing nCRT. More reliable data from prospective studies could lead to the integration of these inexpensive and easy-to-derive tools into clinical practice

The yeast P5 type ATPase, Spf1, regulates manganese transport into the endoplasmic reticulum

The endoplasmic reticulum (ER) is a large, multifunctional and essential organelle. Despite intense research, the function of more than a third of ER proteins remains unknown even in the well-studied model organism Saccharomyces cerevisiae. One such protein is Spf1, which is a highly conserved, ER localized, putative P-type ATPase. Deletion of SPF1 causes a wide variety of phenotypes including severe ER stress suggesting that this protein is essential for the normal function of the ER. The closest homologue of Spf1 is the vacuolar P-type ATPase Ypk9 that influences Mn2+ homeostasis. However in vitro reconstitution assays with Spf1 have not yielded insight into its transport specificity. Here we took an in vivo approach to detect the direct and indirect effects of deleting SPF1. We found a specific reduction in the luminal concentration of Mn2+ in ∆spf1 cells and an increase following it’s overexpression. In agreement with the observed loss of luminal Mn2+ we could observe concurrent reduction in many Mn2+-related process in the ER lumen. Conversely, cytosolic Mn2+-dependent processes were increased. Together, these data support a role for Spf1p in Mn2+ transport in the cell. We also demonstrate that the human sequence homologue, ATP13A1, is a functionally conserved orthologue. Since ATP13A1 is highly expressed in developing neuronal tissues and in the brain, this should help in the study of Mn2+-dependent neurological disorders