Endoplasmic reticulum morphology regulation by RTN4 modulates neuronal regeneration by curbing luminal transport.

Cell functions rely on intracellular transport systems distributing bioactive molecules with high spatiotemporal accuracy. The endoplasmic reticulum (ER) tubular network constitutes a system for delivering luminal solutes, including Ca2+, across the cell periphery. How the ER structure enables this nanofluidic transport system is unclear. Here, we show that ER membrane-localized reticulon 4 (RTN4/Nogo) is sufficient to impose neurite outgrowth inhibition in human cortical neurons while acting as an ER morphoregulator. Improving ER transport visualization methodologies combined with optogenetic Ca2+ dynamics imaging and in silico modeling, we observed that ER luminal transport is modulated by ER tubule narrowing and dilation, proportional to the amount of RTN4. Excess RTN4 limited ER luminal transport and Ca2+ release, while RTN4 elimination reversed the effects. The described morphoregulatory effect of RTN4 defines the capacity of the ER for peripheral Ca2+ delivery for physiological releases and thus may constitute a mechanism for controlling the (re)generation of neurites.

Innate Preferences Affect Results of Object Recognition Task in Wild Type and Alzheimer's Disease Mouse Models.

BACKGROUND: Object recognition task (ORT) is a widely used behavioral paradigm to assess memory in rodent models, due to its easy technical execution, the lack of aversive stressful stimuli, and the possibility to repeat the test on the same animals. However, mouse exploration might be strongly influenced by a variety of variables. OBJECTIVE: To study whether innate preferences influenced exploration in male and female wild type mice and the Alzheimer's disease (AD) model 3xTg. METHODS: We first evaluated how object characteristics (material, size, and shape) influence exploration levels, latency, and exploration modality. Based on these findings, we evaluated whether these innate preferences biased the results of ORT performed in wild type mice and AD models. RESULTS: Assessment of Exploration levels, i.e., the time spent in exploring a certain object in respect to the total exploration time, revealed an innate preference for objects made in shiny materials, such as metal and glass. A preference for bigger objects characterized by higher affordance was also evident, especially in male mice. When performing ORT, exploration was highly influenced by these innate preferences. Indeed, both wild type and AD mice spent more time in exploring the metal object, regardless of its novelty. Furthermore, the use of objects with higher affordance such as the cube was a confounding factor leading to "false" results that distorted ORT interpretation. CONCLUSION: When designing exploration-based behavioral experiments aimed at assessing memory in healthy and AD mice, object characteristics should be carefully evaluated to improve scientific outcomes and minimize possible biases.

Decreased plasma soluble RAGE in patients with hypercholesterolemia: effects of statins.

The receptor for advanced glycation endproducts (RAGE) is overexpressed at sites of vascular pathology. A soluble RAGE isoform (sRAGE) neutralizes the ligand-mediated damage by acting as a decoy. We hypothesized that in hypercholesterolemia up-regulation of the ligand-RAGE axis may bridge impairment of nitric oxide biosynthesis with oxidative stress. We measured in 60 hypercholesterolemic patients and 20 controls plasma total sRAGE levels, urinary 8-iso-prostaglandin (PG) F(2alpha) excretion, and plasma levels of asymmetric dimethylarginine (ADMA). The effects of two structurally different statins (pravastatin and atorvastatin) on these parameters were analyzed in 20 hypercholesterolemic subjects free of vascular disease. Plasma sRAGE was significantly lower, ADMA and urinary 8-iso-PGF(2alpha) were higher, in hypercholesterolemic versus normocholesterolemic patients. Patients on statin treatment with previous myocardial infarction had lower 8-iso-PGF(2alpha), higher sRAGE, and unchanged ADMA levels compared to subjects free of vascular disease. On multivariate regression analysis only 8-iso-PGF(2alpha) and ADMA predicted sRAGE levels. An 8-week treatment with either statin was associated with a significant reduction in urinary 8-iso-PGF(2alpha), whereas only atorvastatin raised sRAGE levels near to normal values, with no change in ADMA levels. sRAGE might serve as an endogenous protecting factor for accelerated atherosclerosis mediated by oxidative stress and endothelial dysfunction in hypercholesterolemia.

Soluble CD40L and cardiovascular risk in asymptomatic low-grade carotid stenosis.

BACKGROUND AND PURPOSE: We investigated whether soluble CD40L (sCD40L) may predict the risk of cardiovascular (CV) events in patients with asymptomatic carotid plaques. METHODS: Forty-two patients with asymptomatic low-grade carotid stenosis (ALCS) and 21 controls without any carotid stenosis were enrolled. All subjects had at least a major cardiovascular risk factor (CRF). Plasma levels of C-reactive protein (CRP), IL-6, and sCD40L were measured. Subjects were reviewed every 12 months (median follow-up, 8 years). RESULTS: ALCS patients had higher (P<0.0001) CRP, IL-6, and sCD40L than controls. Fourteen patients experienced a CV event. Cox regression analysis showed that only high sCD40L levels (P=0.003) independently predicted cardiovascular risk. CONCLUSIONS: High levels of sCD40L may predict the risk of CV events in ALCS.

Acute inflammatory response after inguinal and incisional hernia repair with implantation of polypropylene mesh of different size.

BACKGROUND: The purpose of this study was to assess the modifications of interleukin (IL)-6, C-reactive protein (CRP), leukocytes and fibrinogen after implantation of polypropylene mesh. METHODS: Thirty-six patients were included in this study and divided into two groups. To the first group were allocated patients affected by inguinal hernia and undergoing conventional repair (subgroup Ia) or hernioplasty with 40-cm(2) polypropylene mesh (subgroup Ib). To the second group were allocated patients affected by incisional hernia and undergoing conventional repair (subgroup IIa) or incisional hernia repair with 400-cm(2) polypropylene mesh (subgroup IIb). Peripheral venous blood samples were collected 24 h before surgery and then 6, 24, 48 and 168 h postoperatively. RESULTS: We present evidence that serum levels of IL-6, CRP, leukocytes and fibrinogen were significantly increased postoperatively in all subgroups compared with their baseline values. In particular, the production of inflammatory mediators was higher in subgroups Ib vs Ia and IIb vs IIa. Comparing the entities of the inflammatory responses among various groups we found that it was clear that they were similar in subgroups Ib and IIa, and that the highest were in subgroup IIb and the lowest in subgroup Ia. CONCLUSION: The data show that conventional inguinal and incisional hernia repair induces an inflammatory response, which is smaller than that observed if both operations are carried out with polypropylene meshes. Furthermore, the results suggest that a larger mesh is associated with a higher production of inflammation mediators.

Serum VEGF and b-FGF profiles after tension-free or conventional hernioplasty.

BACKGROUND: Angiogenesis is strongly influenced by vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (b-FGF), whose production is also regulated by interferon (IFN)-gamma and interleukin (IL)-10. The aim of this study was to evaluate the modifications of serum VEGF, b-FGF, IFN-gamma and IL-10 levels in patients with inguinal hernia undergoing hernioplasty with the Lichtenstein technique (LH) using polypropylene mesh or with Bassini open conventional inguinal hernia repair (BH). MATERIALS AND METHODS: Randomly, 16 patients underwent BH, and 16 were treated with the LH technique using polypropylene mesh. Blood samples were collected 24 h prior to surgery and then 6, 24, 48 and 168 h postoperatively. The serum concentrations of VEGF, b-FGF, IFN-gamma and IL-10 were evaluated. RESULTS: In BH patients, a peak of VEGF synthesis at 6 h with a normalization of this parameter 24 h after surgery has been observed. In the same subjects, b-FGF synthesis increased after surgery reaching significant levels 48 h later. On the contrary, in LH patients, a decrease in the serum VEGF and b-FGF concentrations was detected after surgery and their increase afterwards. IL-10 was increased in both groups 6 h after operation and declined to preoperative levels 24 h afterwards. IFN-gamma enhanced in LH patients 6 h after surgery, whereas no modifications were detected in BH subjects. CONCLUSIONS: This preliminary study shows that VEGF and b-FGF modifications, associated with alterations of cytokine secretion, are detectable in human undergoing hernioplasty, and suggests that they could somehow influence in the wound-healing process.