Lymphocytes can self-steer passively with wind vane uropods

International audienceA wide variety of cells migrate directionally in response to chemical or mechanical cues, however the mechanisms involved in cue detection and translation into directed movement are debatable. Here, we investigate a model of lymphocyte migration on the inner surface of blood vessels. Cells orient their migration against fluid flow, suggesting the existence of an adaptive mechano-tranduction mechanism. We find that flow detection may not require molecular mechano-sensors of shear stress and detection of flow direction can be achieved by the orientation in the flow of the non-adherent cell rear, the uropod. Uropods act as microscopic wind vanes that can transmit detection of flow direction into cell steering via the on-going machinery of polarity maintenance, without need for novel internal guidance signalling triggered by flow. Contrary to chemotaxis, which implies active regulation of cue-dependant signalling, upstream flow mechanotaxis of lymphocytes may only rely on a passive self-steering mechanism

Harnessing the Vnn1 pantetheinase pathway boosts short chain fatty acids production and mucosal protection in colitis

Objective In the management of patients with IBD, there is a need to identify prognostic markers and druggable biological pathways to improve mucosal repair and probe the efficacy of tumour necrosis factor alpha biologics. Vnn1 is a pantetheinase that degrades pantetheine to pantothenate (vitamin B 5 , a precursor of coenzyme A (CoA) biosynthesis) and cysteamine. Vnn1 is overexpressed by inflamed colonocytes. We investigated its contribution to the tolerance of the intestinal mucosa to colitis-induced injury. Design We performed an RNA sequencing study on colon biopsy samples from patients with IBD stratified according to clinical severity and modalities of treatment. We generated the VIVA mouse transgenic model, which specifically overexpresses Vnn1 on intestinal epithelial cells and explored its susceptibility to colitis. We developed a pharmacological mimicry of Vnn1 overexpression by administration of Vnn1 derivatives. Results VNN1 overexpression on colonocytes correlates with IBD severity. VIVA mice are resistant to experimentally induced colitis. The pantetheinase activity of Vnn1 is cytoprotective in colon: it enhances CoA regeneration and metabolic adaptation of colonocytes; it favours microbiota-dependent production of short chain fatty acids and mostly butyrate, shown to regulate mucosal energetics and to be reduced in patients with IBD. This prohealing phenotype is recapitulated by treating control mice with the substrate (pantethine) or the products of pantetheinase activity prior to induction of colitis. In severe IBD, the protection conferred by the high induction of VNN1 might be compromised because its enzymatic activity may be limited by lack of available substrates. In addition, we identify the elevation of indoxyl sulfate in urine as a biomarker of Vnn1 overexpression, also detected in patients with IBD. Conclusion The induction of Vnn1/VNN1 during colitis in mouse and human is a compensatory mechanism to reinforce the mucosal barrier. Therefore, enhancement of vitamin B 5-driven metabolism should improve mucosal healing and might increase the efficacy of antiinflammatory therapy

Further Characterization of <i>HDAC</i> and <i>SIRT</i> Gene Expression Patterns in Pancreatic Cancer and Their Relation to Disease Outcome

<div><p>Ductal adenocarcinoma of the pancreas is ranking 4 for patient' death from malignant disease in Western countries, with no satisfactory treatment. We re-examined more precisely the histone deacetylases (<i>HDAC</i>) and Sirtuin (<i>SIRT</i>) gene expression patterns in pancreatic cancer with more pancreatic tumors and normal tissues. We also examinedthe possible relationship between <i>HDAC</i> gene expression levels and long term disease outcome. Moreover, we have evaluated by using an <i>in vitro</i> model system of human pancreatic tumor cell line whether HDAC7 knockdown may affect the cell behavior. We analyzed 29 pancreatic adenocarcinoma (PA), 9 chronic pancreatitis (CP), 8 benign pancreatic (BP) and 11 normal pancreatic tissues. Concerning pancreatic adenocarcinoma, we were able to collect biopsies at the tumor periphery. To assess the possible involvement of HDAC7 in cell proliferation capacity, we have generated recombinant human Panc-1 tumor which underexpressed or overexpressed HDAC7. The expression of <i>HDAC1,2,3,4,7 and Nur77</i> increased in PA samples at levels significantly higher than those observed in the CP group (<i>p</i> = 0.0160; 0.0114; 0.0227; 0.0440; 0.0136; 0.0004, respectively). The expression of HDAC7, was significantly greater in the PA compared with BP tissue samples (<i>p</i> = 0.05). Mean mRNA transcription levels of PA for <i>HDAC7</i> and <i>HDAC2</i> were higher when compared to their counterpart biopsies taken at the tumor periphery (<i>p</i> = 0.0346, 0.0053, respectively). Moreover, the data obtained using confocal microscopy and a quantitative method of immunofluorescence staining strongly support the HDAC7 overexpression in PA surgical specimens. The number of deaths and recurrences at the end of follow up were significantly greater in patients with overexpression of <i>HDAC7</i>. Interestingly, the rate of growth was significantly reduced in the case of cell carrying shRNA construct targeting HDAC7 encoding gene when compared to the parental Panc-1 tumor cells (p = 0.0015) at 48 h and 96 h (p = 0.0021). This study strongly support the notion that HDAC7play a role in pancreatic adenocarcinoma progression.</p></div

Impact of Nurr77 expression on the recurrences the overall survival (A), the disease free survival (B) and recurrences and death in patients with pancreatic adenocarcinoma (C).

<p>N: base line transcription level in CG.</p

Quantitative real-time Q RT-PCR.

<p>Mean Cp of HDACs, SIRTs and Nurr77 genes and 28S transcripts of tissues samples from the control group. qPCR were run in triplicates on two independent cDNA preparations from pancreatic tissues as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0108520#s2" target="_blank">Materials and Methods</a> section. The mean Cp values Ct (mean of Cp) were determined for the following samples: NP-1 to 4, normal pancreas; BD-1 and 2, normal pancreas samples from patients carrying biliary duct tumors. AP-1 to 3: normal adjacent tissues samples ampulloma; G-A: normal adjacent tissues samples after gastric resection for gastric adenocarcinoma; Gastrinoma: normal adjacent tissues samples for gastrinoma of the duodenum.</p

(A) HDACs and Nurr77 genes expression in pancreatic tumor tissues.

<p>(B)SIRT genes expression in pancreatic tumor tissues. Tissue samples from Pancreatic Adenocarcinoma (PA), Benin Tumor (B) and Chronic Pancreatitis (CP). Red line: median of relative RNA transcript levels.</p

Representative results of immunofluorescence staining with HDAC7 mAb (A).

<p>A slight staining is found in NP. In PA, a strong staining is found in the cytoplasm and in association with the cell plasma membrane. Original magnification 250x. Quantitative determination of mean specific fluorescence (MSF) <b>(B)</b>. Six areas in each case were measured. Medians of the MSF intensities obtained with PA and NP tissues are represented by the horizontal lines and the interquartile range is represented by boxes. (* <i>P</i><0.0004).</p

Impact of HDAC2 expression on the overall survival (A), the disease free survival (B) and recurrences and death in patients with pancreatic adenocarcinoma (C).

<p>N: base line transcription level in CG.</p

Expression of HDACs, SIRTs and Nurr77 in pancreatic adenocarcinoma (PA) and control group (CG) by Q RT-PCR.

<p>Samples were run in triplicate on two independent cDNA preparations from pancreatic tissues as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0108520#s2" target="_blank">Materials and Methods</a> section. (Cp) Crossing point values. Comparisons were made by Wilcoxon test and differences were considered significant at p<0.05.</p