Developmental Expression and Dysregulation of miR-146a and miR-155 in Down's Syndrome and Mouse Models of Down's Syndrome and Alzheimer's Disease

BACKGROUND

miR-146a and miR-155 are key regulators of the innate immune response. We hypothesized that an inflammation-mediated dysregulation of these miRNAs may occur in patients with Down syndrome (DS) and Alzheimer's disease (AD).

METHODS

The miRNA expression patterns were investigated by in situ hybridization in developing hippocampus from controls, patients with DS and in adults with AD pathology (DS and sporadic AD; sAD). Quantitative real-time PCR was employed to evaluate the miRNA levels in the hippocampus of sAD and in mouse models of DS and AD. Both miRNAs were expressed in prenatal human hippocampus. In DS we detected increased miR-146a expression in reactive astrocytes. Increased expression of miR-146a was found in the hippocampus of sAD and negatively correlated with its target IRAK-1. APP/PS1 mice showed a significant increase in the expression of both miRNAs at 11-13 months of age as compared to WT and mice at 3 months. A negative correlation between miR-146a levels and its target TRAF6 was observed in both Ts65Dn and APP/PS1 mice.

CONCLUSION

These findings suggest a possible involvement of miR-146a and miR-155 in brain development and neurodegeneration. In particular, we provide evidence of a dysregulation of these two immunomodulatory miRNAs in AD with a potential therapeutical implication, deserving further investigation.

MicroRNA519d and microRNA4758 can identify gangliogliomas from dysembryoplastic neuroepithelial tumours and astrocytomas

Glioneuronal tumours, including gangliogliomas and dysembryoplastic neuroepithelial tumours, represent the most common low-grade epilepsy-associated brain tumours and are a well-recognized cause of intractable focal epilepsy in children and young adults. Classification is predominantly based on histological features, which is difficult due to the broad histological spectrum of these tumours. The aim of the present study was to find molecular markers that can be used to identify entities within the histopathology spectrum of glioneuronal tumours. The focus of this study was on microRNAs (miRNAs). miRNAs are important post-transcriptional regulators of gene expression and are involved in the pathogenesis of different neurological diseases and oncogenesis. Using a miRNA array, miR-519d and miR-4758 were found to be upregulated in gangliogliomas (n=26) compared to control cortex (n=17), peritumoural tissue (n=7), dysembryoplastic neuroepithelial tumours (n=9) and astrocytomas (grade I-IV; subependymal giant cell astrocytomas, n=10; pilocytic astrocytoma, n=15; diffuse astrocytoma grade II, n=10; grade III, n=14 and glioblastoma n=15). Furthermore, the PI3K/AKT3/P21 pathway, which is predicated to be targeted by miR-519d and miR-4758, was deregulated in gangliogliomas. Functionally, overexpression of miR-519d in an astrocytic cell line resulted in a downregulation of CDKN1A (P21) and an increase in cell proliferation, whereas co-transfection with miR-4758 counteracted this effect. These results suggest that miR-519d and miR-4758 might work in concert as regulators of the cell cycle in low grade gliomas. Furthermore, these miRNAs could be used to distinguish gangliogliomas from dysembryoplastic neuroepithelial tumours and other low and high grade gliomas and may lead to more targeted therapy.

In Vitro Interleukin-8 Production by Monocytes Treated with Lithium Chloride from Breast Cancer Patients

Aims and background

Since interleukin-8 (IL-8) has a suppressive effect on hematopoiesis, lithium induces leukocytosis and granulocytosis and mononuclear cells are defective in patients affected by neoplastic disease, we analyzed IL-8 production by monocytes obtained from patients with non-metastatic breast cancer (BCaMO) and metastatic breast cancer (BCaM1) and the effect of lithium chloride (LiCI) on these cells. Lithium salt compounds are used to limit the degree and duration of neutropenia in patients receiving chemotherapy for cancer and acute leukemia. Lithium influences the hematopoietic system, which is known to be regulated by numerous cytokines including IL-8.

Methods

We selected three groups of subjects (15 per group): patients affected by BCaMO, BCaM1 and healthy donors (HD) matched for sex and age. IL-8 release was assessed in supernatants of lipopolysaccharide (LPS) and/or LiCI-treated monocyte cultures.

Results

Monocytes from BCaM1 released higher IL-8 levels than monocytes from BCaMO (P <0.0001); the IL-8 levels of both groups were significantly higher (P <0.0001) than those of HD. In vitro LiCI treatment reduced IL-8 production by monocytes obtained from all subjects compared to the same cells when untreated or LPS treated. The suppressive effect of LiCI on IL-8 production by monocytes from breast cancer patients was particularly marked in monocytes from BCaMO with respect to those from BCaM1. LPS treatment increased the IL-8 production more in BCaM1 monocytes than in BCaMO monocytes. Moreover, combined LPS/LiCI treatment of monocytes significantly (P <0.0001) downregulated the release of IL-8 compared to treatment with LPS alone.

Conclusions

Our data demonstrate that monocytes from BCaM1 release larger amounts of IL-8 than monocytes from BCaMO and from HD. Lithium was able to downregulate IL-8 production by monocytes from different subgroups. Further studies are needed to clarify if the improvement of the hematopoietic system in vivo observed following lithium therapy could reside, at least in part, in the ability of lithium to downregulate this chemokine.

Disturbance of redox homeostasis in Down Syndrome: Role of iron dysmetabolism

Down Syndrome (DS) is the most common genetic form of intellectual disability that leads in the majority of cases to development of early-onset Alzheimer-like dementia (AD). The neuropathology of DS has several common features with AD including alteration of redox homeostasis, mitochondrial deficits, and inflammation among others. Interestingly, some of the genes encoded by chromosome 21 are responsible of increased oxidative stress (OS) conditions that are further exacerbated by decreased antioxidant defense. Previous studies from our groups showed that accumulation of oxidative damage is an early event in DS neurodegeneration and that oxidative modifications of selected proteins affects the integrity of the protein degradative systems, antioxidant response, neuronal integrity and energy metabolism. In particular, the current review elaborates recent findings demonstrating the accumulation of oxidative damage in DS and we focus attention on specific deregulation of iron metabolism, which affects both the central nervous system and the periphery. Iron dysmetabolism is a well-recognized factor that contributes to neurodegeneration; thus we opine that better understanding how and to what extent the concerted loss of iron dyshomeostasis and increased OS occur in DS could provide novel insights for the development of therapeutic strategies for the treatment of Alzheimer-like dementia.

Jaccoud's arthropathy, an unusual manifestation of idiopathic retroperitoneal fibrosis: rapid improvement of symptoms after tocilizumab treatment

Jaccoud's arthropathy (JA) is a chronic, non erosive, rheumatoid-like deformity associated with rheumatic fever (RF) and systemic lupus erythematosus and with other diseases such as psoriatic arthritis, connective tissue diseases, hypocomplementemic urticarial vasculitis, infections, sarcoidosis and neoplasia. We described a case of JA in a patient with cutaneous psoriasis but with a particular disease evolution associated with idiopathic retropritoneal fibrosis (IRF), evaluated with computed tomography, magnetic resonance and 18F-FDG PET/ CT. The patient, following failure with steroids, methotrexate and etanercept, was treated with tocilizumab (8 mg/kg) once every 4 weeks for 6 months. A rapid improvement of symptoms and disappearance of 18F-FDG uptake was shown. We describe a review of literature of rheumatic manifestations of IRF and the possible role of interleukin-6 in the pathway of JA and IRF.

Polyubiquitinylation Profile in Down Syndrome Brain Before and After the Development of Alzheimer Neuropathology

AIMS

Among the putative mechanisms proposed to be common factors in Down syndrome (DS) and Alzheimer's disease (AD) neuropathology, deficits in protein quality control (PQC) have emerged as a unifying mechanism of neurodegeneration. Considering that disturbance of protein degradation systems is present in DS and that oxidized/misfolded proteins require polyubiquitinylation for degradation via the ubiquitin proteasome system, this study investigated if dysregulation of protein polyubiquitinylation is associated with AD neurodegeneration in DS.

RESULTS

Postmortem brains from DS cases before and after development of AD neuropathology and age-matched controls were analyzed. By selectively isolating polyubiquitinated proteins, we were able to identify specific proteins with an altered pattern of polyubiquitinylation as a function of age. Interestingly, we found that oxidation is coupled with polyubiquitinylation for most proteins mainly involved in PQC and energy metabolism.

INNOVATION

This is the first study showing alteration of the polyubiquitinylation profile as a function of aging in DS brain compared with healthy controls. Understanding the onset of the altered ubiquitome profile in DS brain may contribute to identification of key molecular regulators of age-associated cognitive decline.

CONCLUSIONS

Disturbance of the polyubiquitinylation machinery may be a key feature of aging and neurodegeneration. In DS, age-associated deficits of the proteolytic system may further exacerbate the accumulation of oxidized/misfolded/polyubiquitinated proteins, which is not efficiently degraded and may become harmful to neurons and contribute to AD neuropathology. Antioxid. Redox Signal. 26, 280-298.

Activation of p53 in Down Syndrome and in the Ts65Dn Mouse Brain is Associated with a Pro-Apoptotic Phenotype

Down syndrome (DS) is the most common genetic cause of intellectual disability, resulting from trisomy of chromosome 21. The main feature of DS neuropathology includes early onset of Alzheimer's disease (AD), with deposition of senile plaques and tangles. We hypothesized that apoptosis may be activated in the presence of AD neuropathology in DS, thus we measured proteins associated with upstream and downstream pathways of p53 in the frontal cortex from DS cases with and without AD pathology and from Ts65Dn mice, at different ages. We observed increased acetylation and phosphorylation of p53, coupled to reduced MDM2/p53 complex level and lower levels of SIRT1. Activation of p53 was associated with a number of targets (BAX, PARP1, caspase-3, p21, heat shock proteins, and PGC1α) that were modulated in both DS and DS/AD compared with age-matched controls. In particular, the most relevant changes (increased p-p53 and acetyl-p53 and reduced formation of MDM2/p53 complex) were found to be modified only in the presence of AD pathology in DS. In addition, a similar pattern of alterations in the p53 pathway was found in Ts65Dn mice. These results suggest that p53 may integrate different signals, which can result in a pro-apoptotic-phenotype contributing to AD neuropathology in people with DS.

Aseptic HLA B27-positive spondylodiscitis: decreased 18F-FDG uptake after etanercept treatment

We observed a 69-year old man suffering from HLA B27 ankylosing spondylitis with persistent night back pain. 18F-FDG-PET/CT showed an increased metabolism at the level of the spinal space of L2-L3, L3-L4 with increased uptake compatible with spondylodiscitis. He started therapy with etanercept 50 mg/week. After six months of treatment repeated testing showed no uptake of the discs and vertebral bodies.

Shrimp Allergy: Analysis of Commercially Available Extracts for In Vivo Diagnosis

BACKGROUND AND OBJECTIVE

Skin prick testing (SPT) with commercial extracts is the first step in the diagnosis of shrimp allergy, although its clinical efficiency is unknown. Objective: To analyze the clinical usefulness of all commercial crustacean extracts available for SPT in Italy.

METHODS

We performed a multicenter study of 157 shrimp-allergic patients who underwent SPT with 5 commercial crustacean extracts and with house dust mite (HDM) extract. Commercial extracts were analyzed using SDS-PAGE and compared with a freshly prepared in-house shrimp extract. IgE to Pen a 1/Pen m 1, Pen m 2, and Pen m 4 was determined, and immunoblot analysis was performed on a large number of sera.

RESULTS

The skin reactions caused by commercial crustacean extracts were extremely heterogeneous, resulting in 32 clinical profiles, with marked differences in protein content and missing proteins at molecular weights corresponding to those of major shrimp allergens. Only strong Pen a 1/Pen m 1 reactors reacted to both HDM and all 5 commercial extracts in SPT. Most patients, including those who were tropomyosin-negative, reacted to HDM. Patients reacted to a large and variable array of proteins, and IgE reactivity was common at high molecular weights (>50 kDa).

CONCLUSIONS

The in vivo diagnosis of shrimp allergy must continue to be based on SPT with fresh material. Shrimp-allergic patients frequently react to a number of ill-defined high-molecular-weight allergens, thus leaving currently available materials for component-resolved diagnosis largely insufficient. Mites and crustaceans probably share several allergens other than tropomyosin.

Impairment of biliverdin reductase-A promotes brain insulin resistance in Alzheimer disease: A new paradigm

Clinical studies suggest a link between peripheral insulin resistance and cognitive dysfunction. Interestingly, post-mortem analyses of Alzheimer disease (AD) subjects demonstrated insulin resistance in the brain proposing a role for cognitive deficits observed in AD. However, the mechanisms responsible for the onset of brain insulin resistance (BIR) need further elucidations. Biliverdin reductase-A (BVR-A) emerged as a unique Ser/Thr/Tyr kinase directly involved in the insulin signaling and represents an up-stream regulator of the insulin signaling cascade. Because we previously demonstrated the oxidative stress (OS)-induced impairment of BVR-A in human AD brain, we hypothesize that BVR-A dysregulation could be associated with the onset of BIR in AD. In the present work, we longitudinally analyze the age-dependent changes of (i) BVR-A protein levels and activation, (ii) total oxidative stress markers levels (PC, HNE, 3-NT) as well as (iii) IR/IRS1 levels and activation in the hippocampus of the triple transgenic model of AD (3xTg-AD) mice. Furthermore, ad hoc experiments have been performed in SH-SY5Y neuroblastoma cells to clarify the molecular mechanism(s) underlying changes observed in mice. Our results show that OS-induced impairment of BVR-A kinase activity is an early event, which starts prior the accumulation of Aβ and tau pathology or the elevation of TNF-α, and that greatly contribute to the onset of BIR along the progression of AD pathology in 3xTg-Ad mice. Based on these evidence we, therefore, propose a new paradigm for which: OS-induced impairment of BVR-A is firstly responsible for a sustained activation of IRS1, which then causes the stimulation of negative feedback mechanisms (i.e. mTOR) aimed to turn-off IRS1 hyper-activity and thus BIR. Similar alterations characterize also the normal aging process in mice, positing BVR-A impairment as a possible bridge in the transition from normal aging to AD.

Increased Mammalian Target of Rapamycin Signaling Contributes to the Accumulation of Protein Oxidative Damage in a Mouse Model of Down's Syndrome

BACKGROUND

Neurodegenerative diseases are characterized by increased levels of oxidative stress and an altered mammalian target of rapamycin (mTOR)/autophagy axis; however, the mutual relationship between these two events is controversial. Previous studies in Down's syndrome (DS) and Alzheimer's disease (AD) suggested that the accumulation of protein oxidative damage results from the increased free radical production, mainly related to metabolic alterations, mitochondrial degeneration and amyloid-β deposition, and aberrant activity of protein degradative systems.

SUMMARY

This study analyzed mTOR signaling in Ts65Dn mice, a model of DS, at 6 and 12 months of age compared with euploid mice showing the early aberrant hyperphosphorylation of mTOR coupled with the reduction of autophagosome formation. Moreover, the evaluation of protein oxidation shows an increase in protein nitration and protein-bound 4-hydroxynonenal in 12-month-old Ts65Dn mice suggesting the potential involvement of altered autophagy in the buildup of protein oxidative damage. In addition, data obtained on cell culture support the protective role of autophagy in reducing protein oxidation.

KEY MESSAGES

Overall, this study provides further evidence for the role of mTOR hyperactivation and reduced autophagy in the accumulation of protein oxidative damage during DS and AD pathologies.

Bach1 overexpression in Down syndrome correlates with the alteration of the HO-1/BVR-a system: insights for transition to Alzheimer's disease

Bach1, among the genes encoded on chromosome 21, is a transcription repressor, which binds to antioxidant response elements of DNA thus inhibiting the transcription of specific genes involved in the cell stress response including heme oxygenase-1 (HO-1). HO-1 and its partner, biliverdin reductase-A (BVR-A), are upregulated in response to oxidative stress in order to protect cells against further damage. Since oxidative stress is an early event in Down syndrome (DS) and might contribute to the development of multiple deleterious DS phenotypes, including Alzheimer's disease (AD) pathology, we investigated the status of the Bach1/HO-1/BVR-A axis in DS and its possible implications for the development of AD. In the present study, we showed increased total Bach1 protein levels in the brain of all DS cases coupled with reduced induction of brain HO-1. Furthermore, increased oxidative stress could, on one hand, overcome the inhibitory effects of Bach1 and, on the other hand, promote BVR-A impairment. Our data show that the development of AD in DS subjects is characterized by (i) increased Bach1 total and poly-ubiquitination; (ii) increased HO-1 protein levels; and (iii) increased nitration of BVR-A followed by reduced activity. To corroborate our findings, we analyzed Bach1, HO-1, and BVR-A status in the Ts65Dn mouse model at 3 (young) and 15 (old) months of age. The above data support the hypothesis that the dysregulation of HO-1/BVR-A system contributes to the early increase of oxidative stress in DS and provide potential mechanistic paths involved in the neurodegenerative process and AD development.

Systemic nickel allergy syndrome: epidemiological data from four Italian allergy units

The prevalence of nickel hyper-sensitivity varies widely in different countries, nevertheless it is the leading cause of contact dermatitis. The presence of nickel in the diet (mainly plant foods) in some nickel-sensitive subjects can provoke/aggravate eczema and systemic contact dermatitis as well as cause extra-cutaneous symptoms (respiratory, gastrointestinal, neurological). These symptoms, correlated to the ingestion of nickel-containing foods and beverages, in nickel patch test positive individuals, defines the so called Systemic Nickel Allergy Syndrome (SNAS), a condition successfully treated by oral desensitization. Although numerous studies have investigated the prevalence of contact nickel allergy or addressed the relationship between nickel intake and onset of systemic symptoms, to our knowledge no epidemiological studies have attempted to estimate the prevalence of SNAS. Therefore, we decided to evaluate consecutive patients (1,696), afferent to four allergy units in Sicily, a region of southern Italy, from October 2010 to March 2011. SNAS was confirmed in 98 patients (5.78 percent) of the 1,696 studied, suggesting that this clinical entity may be an emergent allergological condition rather than an occasional finding. The most common symptoms complained of in our population were cutaneous (51 patients), gastrointestinal (87 patients) and other systemic clinical manifestations (37 patients). Furthermore, 16 out of the 98 SNAS patients (16.3 percent) presented IgE-mediated food allergy with a statistically significant association (X2=16.950; P<0.0001), therefore suggesting underlying cross-facilitating pathways. These findings need confirmation on wider populations but may help allergists to suspect, during common clinical practice, that cutaneous and extra-cutaneous symptoms may be referred to nickel intake and deserve specific in-depth investigation.

Heterogenity of IgE response to walnut and hazelnut in Italian allergic patients

BACKGROUND

The prevalence of IgE reactivity against genuine walnut and hazelnut allergens is poorly defined.

OBJECTIVE

The IgE response to walnut and hazelnut was investigated in Italian patients with primary allergy to these nuts.

METHODS

Sera from 36 patients allergic to hazelnut and/or walnut, not reactive to PR-10, profilin, and LTP, underwent immunoblot analysis with extracts of both nuts.

RESULTS

Most patients had a history of systemic symptoms following the ingestion of the offending food(s). Twelve patients were sensitized to both walnut and hazelnut, and 13 were sensitized to other nuts and seeds (cashew, peanut, sesame, pine nut, almond, Brazil nut, and pistachio). On walnut immunoblot, the 7 sera which scored positive showed much variability in their IgE profile. Two reacted uniquely at 10 kDa, and the others at 35 , 40, 45, 50, 67, and > 67 kDa. The profiles obtained under reducing and non-reducing conditions showed several differences. The 7 sera positive on hazelnut immunoblot under reducing conditions recognized sera at 10 kDa and at <10 kDa (n=1), 20 kDa (n=4), at about 22, 24, 30, 40, 43, 58, 60, and 90 kDa, and higher m.w. in other cases. Under non-reducing conditions IgE reactivity at 20, 28, 35, 40, 45, 60, 90, and 100 kDa, was detected. Only two sera scored positive under both conditions and showed an IgE profile that partly changed from one assay to another.

CONCLUSION

The current list of walnut and hazelnut allergens is far from being complete. Both reducing and non-reducing conditions are needed to detect IgE reactivity in individual patients.

The effects of age on the spatial and temporal integration of global motion

The purpose of this study was to determine the relative contributions of local element speed and/or spatial displacement to age-related deficits in global motion processing. Motion coherence thresholds (79% correct) were measured for discriminating the direction of translational random dot kinematograms (RDKs) as a function of dot speed and spatial displacement across the adult lifespan (20-79 years). Age-related impairments in global motion processing were only apparent in observers 70-79 years of age. In agreement with previous studies, we found an age-related impairment at low (0.625 deg/s) and high speeds (10 deg/s). However, these effects were heavily mediated by dot spatial displacement. Motion coherence thresholds were also most markedly elevated in women aged over 70 years. These findings suggest a prominent role of spatial integration in global motion processing. Moreover, global motion perception appears to be relatively well preserved until around 70 years of age.