Post-COVID-19 Hyposmia Does Not Exhibit Main Neurodegeneration Markers in the Olfactory Pathway

The biological substrate of persistent post-COVID-19 hyposmia is still unclear. However, as many neurodegenerative diseases present with smell impairment at onset, it may theoretically reflect degeneration within the central olfactory circuits. However, no data still exist regarding the post-COVID-19 patients. As the olfactory neurons (ONs) mirror pathological changes in the brain, allowing for tracking the underlying molecular events, here, we performed a broad analysis of ONs from patients with persistent post-COVID-19 OD to identify traces of potential neurodegeneration. ONs were collected through the non-invasive brushing of the olfactory mucosa from ten patients with persistent post-COVID-19 hyposmia (lasting > 6 months after infection) and ten age/sex-matched controls. Immunofluorescence staining for protein quantification and RT-PCR for gene expression levels were combined to measure ONs markers of α-synuclein, amyloid-β, and tau pathology, axonal injury, and mitochondrial network. Patients and controls had similar ONs levels of oligomeric α-synuclein, amyloid-β peptide, tau protein, neurofilament light chain (NfL), cytochrome C oxidase subunit 3 (COX3), and the heat shock protein 60 (HSP60). Our findings thus did not provide evidence for synucleinopathy and amyloid-β mismetabolism or gross traces of neuronal injury and mitochondrial dysfunction within the olfactory system in the early phase of persistent post-COVID-19 hyposmia.

HAX1 is a novel binding partner of Che-1/AATF. Implications in oxidative stress cell response

HAX1 is a multifunctional protein involved in the antagonism of apoptosis in cellular response to oxidative stress. In the present study we identified HAX1 as a novel binding partner for Che-1/AATF, a pro-survival factor which plays a crucial role in fundamental processes, including response to multiple stresses and apoptosis. HAX1 and Che-1 proteins show extensive colocalization in mitochondria and we demonstrated that their association is strengthened after oxidative stress stimuli. Interestingly, in MCF-7 cells, resembling luminal estrogen receptor (ER) positive breast cancer, we found that Che-1 depletion correlates with decreased HAX1 mRNA and protein levels, and this event is not significantly affected by oxidative stress induction. Furthermore, we observed an enhancement of the previously reported interaction between HAX1 and estrogen receptor alpha (ERα) upon H2O2 treatment. These results indicate the two anti-apoptotic proteins HAX1 and Che-1 as coordinated players in cellular response to oxidative stress with a potential role in estrogen sensitive breast cancer cells.

Reduced expression of secretogranin VGF in laryngeal squamous cell carcinoma

Laryngeal cancer accounts for one-third of all head and neck tumors, with squamous cell carcinoma (SCC) being the most predominant type, followed by neuroendocrine tumors. Chromogranins, are commonly used as biomarkers for neuroendocrine tumors, including laryngeal cancer. It has been reported that secretogranin VGF, a member of the chromogranin family, can be also used as a significant biomarker for neuroendocrine tumors. However, the expression and role of VGF in laryngeal carcinomas have not been previously investigated. Therefore, the present study aimed to determine the expression levels of VGF in laryngeal SCC (LSCC). The present study collected tumor tissues, as well as serum samples, from a cohort of 15 patients with LSCC. The results of reverse transcription-quantitative PCR, western blot analysis and immunofluorescence assays showed that the selective VGF precursor was downregulated in patients with LSCC. Notably, in tumor tissue, the immunoreactivity for VGF was found in vimentin-positive cells, probably corresponding to T lymphocytes. The current preliminary study suggested that the reduced expression levels of VGF observed in tumor tissue and at the systemic level could sustain LSCC phenotype. Overall, VGF could be a potential biomarker for detecting neoplastic lesions with a higher risk of tumor invasiveness, even in non-neuroendocrine tumors.

Investigating Biomarkers for COVID-19 Morbidity and Mortality

BACKGROUND AND OBJECTIVE

This retrospective study aims to disclose further early parameters of COVID-19 morbidity and mortality.

METHODS

Three hundred and eighty-two COVID-19 patients, recruited between March and April 2020, were divided into three groups according to their outcome: (1) hospital ward group (patients who entered the hospital wards and survived); (2) intensive care unit (ICU) group (patients who attended the ICU and survived); (3) the deceased group (patients admitted to ICU with a fatal outcome). We investigated routine laboratory parameters such as albumin, glycemia, hemoglobin amylase, lipase, AST, ALT, GGT, LDH, CK, MGB, TnT-hs, IL-6, ferritin, CRP, PCT, WBC, RBC, PLT, PT, INR, APTT, FBG, and D-dimer. Blood withdrawal was carried out at the beginning of the hospitalization period.

RESULTS

ANOVA and ROC data evidenced that the concomitant presence of alterations in albumin, lipase, AST, ALT, LDH, MGB, CK, IL-6, ferritin in women, CRP and D-dimer is an early sign of fatal outcomes.

CONCLUSION

The present study confirms and extends the validity of routine laboratory biomarkers (i.e., lipase, AST, ALT, LDH, CK, IL-6, ferritin in women, CRP and D-dimer) as indicators of COVID-19 morbidity and mortality. Furthermore, the investigation suggests that both gross changes in albumin and MGB, markers of liver and heart damage, may early disclose COVID-19 fatal outcomes.

SMN Deficiency Destabilizes ABCA1 Expression in Human Fibroblasts: Novel Insights in Pathophysiology of Spinal Muscular Atrophy

The deficiency of survival motor neuron protein (SMN) causes spinal muscular atrophy (SMA), a rare neuromuscular disease that affects different organs. SMN is a key player in RNA metabolism regulation. An intriguing aspect of SMN function is its relationship with plasma membrane-associated proteins. Here, we provide a first demonstration that SMN affects the ATP-binding cassette transporter A1, (ABCA1), a membrane protein critically involved in cholesterol homeostasis. In human fibroblasts, we showed that SMN associates to ABCA1 mRNA, and impacts its subcellular distribution. Consistent with the central role of ABCA1 in the efflux of free cholesterol from cells, we observed a cholesterol accumulation in SMN-depleted human fibroblasts. These results were also confirmed in SMA type I patient-derived fibroblasts. These findings not only validate the intimate connection between SMN and plasma membrane-associated proteins, but also highlight a contribution of dysregulated cholesterol efflux in SMA pathophysiology.

The RNA-Binding Protein SMN as a Novel Player in Laryngeal Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) arises from the mucosal epithelium in the oral cavity, pharynx, sino-nasal region, and larynx. Laryngeal squamous cell carcinoma (LSCC) represents one-third of all head and neck cancers. Dysregulated RNA-related pathways define an important molecular signature in this aggressive carcinoma. The Survival Motor Neuron (SMN) protein regulates fundamental aspects of the RNA metabolism but, curiously, its role in cancer is virtually unknown. For the first time, here, we focus on the SMN in the cancer context. We conducted a pilot study in a total of 20 patients with LSCC where the SMN was found overexpressed at both the protein and transcript levels. By a cellular model of human laryngeal carcinoma, we demonstrated that the SMN impacts cancer-relevant behaviors and perturbs key players of cell migration, invasion, and adhesion. Furthermore, in LSCC we showed a physical interaction between the SMN and the epidermal growth factor receptor (EGFR), whose overexpression is an important feature in these tumors. This study proposes the SMN protein as a novel therapeutic target in LSSC and likely in the whole spectrum of HNSCC. Overall, we provide the first analysis of the SMN in human cancer.

Neuroimmune Dysregulation in Prepubertal and Adolescent Individuals Affected by Klinefelter Syndrome

BACKGROUND

The syndrome Klinefelter syndrome (KS) is a genetic disorder due to an extra X chromosome in males. Many cases remain undiagnosed until the onset of major manifestations, which include hypergonadotropic hypogonadism and infertility. This condition is associated with many comorbidities that involve the cardiovascular, endocrine, and immune systems. Last but not the least, individuals with KS show a high risk of developing psychiatric and mood disorders in adult age.

OBJECTIVE

While many studies are accessible on KS in adult individuals, the neuroinflammatory condition in adolescent and prepubertal KS individuals is not fully known.

METHODS

Our study aims to evaluate in prepubertal and adolescent KS individuals, for the first time, the levels of the serum of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), cytokines having subtle roles in oxidative processes, and neuroinflammation with respect to the levels of TNF-α, TGF-β, MCP-1, IL-1α, IL-2, IL-6, IL-10, and IL-12 and oxidative stress by employing free oxygen radicals defense and free oxygen radicals test.

RESULTS

We found no changes in NGF and oxidative stress parameters, but BDNF decreased compared to healthy children. Quite interestingly, our data showed reduced levels of IL-2, IL-1α, IL- 12, IL-10, and IL-6 in prepubertal KS children.

CONCLUSION

The present study discloses disrupted immune system and neurotrophin pathways in KS children.

Characteristic Hallmarks of Aging and the Impact on Carcinogenesis

Evidence shows that there is a synergistic, bidirectional association between cancer and aging with many shared traits. Age itself is a risk factor for the onset of most cancers, while evidence suggests that cancer and its treatments might accelerate aging by causing genotoxic and cytotoxic insults. Aging has been associated with a series of alterations that can be linked to cancer: i) genomic instability caused by DNA damage or epigenetic alterations coupled with repair errors, which lead to progressive accumulation of mutations; ii) telomere attrition with possible impairment of telomerase, shelterin complex, or the trimeric complex (Cdc13, Stn1 and Ten1 - CST) activities associated with abnormalities in DNA replication and repair; iii) altered proteostasis, especially when leading to an augmented proteasome, chaperon and autophagy-lysosome activity; iv) mitochondrial dysfunction causing oxidative stress; v) cellular senescence; vi) stem cells exhaustion, intercellular altered communication and deregulated nutrient sensing which are associated with microenvironmental modifications which may facilitate the subsequential role of cancer stem cells. Nowadays, anti-growth factor agents and epigenetic therapies seem to assume an increasing role in fighting aging-related diseases, especially cancer. This report aims to discuss the impact of age on cancer growth.

Serum NGF and BDNF in Long-COVID-19 Adolescents: A Pilot Study

COVID-19 (COronaVIrus Disease 19) is an infectious disease also known as an acute respiratory syndrome caused by the SARS-CoV-2. Although in children and adolescents SARS-CoV-2 infection produces mostly mild or moderate symptoms, in a certain percentage of recovered young people a condition of malaise, defined as long-COVID-19, remains. To date, the risk factors for the development of long-COVID-19 are not completely elucidated. Neurotrophins such as NGF (Nerve Growth Factor) and BDNF (Brain-Derived Neurotrophic Factor) are known to regulate not only neuronal growth, survival and plasticity, but also to influence cardiovascular, immune, and endocrine systems in physiological and/or pathological conditions; to date only a few papers have discussed their potential role in COVID-19. In the present pilot study, we aimed to identify NGF and BDNF changes in the serum of a small cohort of male and female adolescents that contracted the infection during the second wave of the pandemic (between September and October 2020), notably in the absence of available vaccines. Blood withdrawal was carried out when the recruited adolescents tested negative for the SARS-CoV-2 (“post-infected COVID-19”), 30 to 35 days after the last molecular test. According to their COVID-19 related outcomes, the recruited individuals were divided into three groups: asymptomatics, acute symptomatics and symptomatics that over time developed long-COVID-19 symptoms (“future long-COVID-19”). As a control group, we analyzed the serum of age-matched healthy controls that did not contract the infection. Inflammatory biomarkers (TNF-α, TGF-β), MCP-1, IL-1α, IL-2, IL-6, IL-10, IL-12) were also analyzed with the free oxygen radicals’ presence as an oxidative stress index. We showed that NGF serum content was lower in post-infected-COVID-19 individuals when compared to healthy controls; BDNF levels were found to be higher compared to healthy individuals only in post-infected-COVID-19 symptomatic and future long-COVID-19 girls, leaving the BDNF levels unchanged in asymptomatic individuals if compared to controls. Oxidative stress and inflammatory biomarkers were unchanged in male and female adolescents, except for TGF-β that, similarly to BDNF, was higher in post-infected-COVID-19 symptomatic and future long-COVID-19 girls. We predicted that NGF and/or BDNF could be used as early biomarkers of COVID-19 morbidity in adolescents.

Exploring Mitochondrial Localization of SARS-CoV-2 RNA by Padlock Assay: A Pilot Study in Human Placenta

The ongoing COVID-19 pandemic dictated new priorities in biomedicine research. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, is a single-stranded positive-sense RNA virus. In this pilot study, we optimized our padlock assay to visualize genomic and subgenomic regions using formalin-fixed paraffin-embedded placental samples obtained from a confirmed case of COVID-19. SARS-CoV-2 RNA was localized in trophoblastic cells. We also checked the presence of the virion by immunolocalization of its glycoprotein spike. In addition, we imaged mitochondria of placental villi keeping in mind that the mitochondrion has been suggested as a potential residence of the SARS-CoV-2 genome. We observed a substantial overlapping of SARS-CoV-2 RNA and mitochondria in trophoblastic cells. This intriguing linkage correlated with an aberrant mitochondrial network. Overall, to the best of our knowledge, this is the first study that provides evidence of colocalization of the SARS-CoV-2 genome and mitochondria in SARS-CoV-2 infected tissue. These findings also support the notion that SARS-CoV-2 infection can reprogram mitochondrial activity in the highly specialized maternal–fetal interface.

Early Routine Biomarkers of SARS-CoV-2 Morbidity and Mortality: Outcomes from an Emergency Section

Background. COVID-19 is a severe acute respiratory disease caused by SARS-CoV-2, a virus belonging to the Coronaviridae family. This disease has spread rapidly around the world and soon became an international public health emergency leading to an unpredicted pressure on the hospital emergency units. Early routine blood biomarkers could be key predicting factors of COVID-19 morbidity and mortality as suggested for C-reactive protein (CRP), IL-6, prothrombin and D-dimer. This study aims to identify other early routine blood biomarkers for COVID-19 severity prediction disclosed directly into the emergency section. Methods. Our research was conducted on 156 COVID-19 patients hospitalized at the Sapienza University Hospital “Policlinico Umberto I” of Rome, Italy, between March 2020 and April 2020 during the paroxysm’s initial phase of the pandemic. In this retrospective study, patients were divided into three groups according to their outcome: (1) emergency group (patients who entered the emergency room and were discharged shortly after because they did not show severe symptoms); (2) intensive care unit (ICU) group (patients who attended the ICU after admission to the emergency unit); (3) the deceased group (patients with a fatal outcome who attended the emergency and, afterward, the ICU units). Routine laboratory tests from medical records were collected when patients were admitted to the emergency unit. We focused on Aspartate transaminase (AST), Alanine transaminase (ALT), Lactate dehydrogenase (LDH), Creatine kinase (CK), Myoglobin (MGB), Ferritin, CRP, and D-dimer. Results. As expected, ANOVA data show an age morbidity increase in both ICU and deceased groups compared with the emergency group. A main effect of morbidity was revealed by ANOVA for all the analyzed parameters with an elevation between the emergency group and the deceased group. Furthermore, a significant increase in LDH, Ferritin, CRP, and D-dimer was also observed between the ICU group and the emergency group and between the deceased group and ICU group. Receiver operating characteristic (ROC) analyses confirmed and extended these findings. Conclusions. This study suggests that the contemporaneous presence of high levels of LDH, Ferritin, and as expected, CRP, and D-dimer could be considered as potential predictors of COVID-19 severity and death.

Fine-Tuning of mTOR mRNA and Nucleolin Complexes by SMN

Increasing evidence points to the Survival Motor Neuron (SMN) protein as a key determinant of translation pathway. Besides its role in RNA processing and sorting, several works support a critical implication of SMN in ribosome biogenesis. We previously showed that SMN binds ribosomal proteins (RPs) as well as their encoding transcripts, ensuring an appropriate level of locally synthesized RPs. SMN impacts the translation machinery in both neural and non-neural cells, in agreement with the concept that SMN is an essential protein in all cell types. Here, we further assessed the relationship between SMN and translation-related factors in immortalized human fibroblasts. We focused on SMN-nucleolin interaction, keeping in mind that nucleolin is an RNA-binding protein, highly abundant within the nucleolus, that exhibits a central role in ribosomes production. Nucleolin may also affects translation network by binding the mammalian target of rapamycin (mTOR) mRNA and promoting its local synthesis. In this regard, for the first time we provided evidence that SMN protein itself associates with mTOR transcript. Collectively, we found that: (1) SMN coexists with nucleolin-mTOR mRNA complexes at subcellular level; (2) SMN deficiency impairs nucleolar compartmentalization of nucleolin, and (3) this event correlates with the nuclear retention of mTOR mRNA. These findings suggest that SMN may regulate not only structural components of translation machinery, but also their upstream regulating factors.

Mediterranean Diet, Brain and Muscle: Olive Polyphenols and Resveratrol Protection in Neurodegenerative and Neuromuscular Disorders

The Mediterranean diet is worldwide recognized as a good prototype of nutrition due to the conspicuous intake of olive oil, nuts, red wine, legumes, fruit, and vegetables, all fundamental elements rich in antioxidant substances and polyphenols. Polyphenols are a wide range of phytochemicals and/or synthetic chemical compounds with proven beneficial properties for human health. In the present review, we critically summarize the well-characterized antioxidant and anti-inflammatory properties of polyphenols contained in the olives and extra virgin olive oil and of resveratrol, a non-flavonoid phenolic compound. We discussed the potential use of these polyphenols as pharmaceutical formulations for the treatment of human diseases. We also show the emerging importance of their consumption in the prevention and management of crucial neurodegenerative conditions (alcohol-related brain disorders and aging) and in neuromuscular disorders (Spinal Muscular Atrophy and Amyotrophic Lateral Sclerosis and Duchenne Muscular Dystrophy), where oxidative stress plays a predominant role.

Identification of protein/mRNA network involving the PSORS1 locus gene CCHCR1 and the PSORS4 locus gene HAX1

CCHCR1 (Coiled-Coil alpha-Helical Rod 1), maps to chromosomal region 6p21.3, within the major psoriasis susceptibility locus PSORS1. CCHCR1 itself is a plausible psoriasis candidate gene, however its role in psoriasis pathogenesis remains unclear. We previously demonstrated that CCHCR1 protein acts as a cytoplasmic docking site for RNA polymerase II core subunit 3 (RPB3) in cycling cells, suggesting a role for CCHCR1 in vesicular trafficking between cellular compartments. Here, we report a novel interaction between CCHCR1 and the RNA binding protein HAX1. HAX1 maps to chromosomal region 1q21.3 within the PSORS4 locus and is over-expressed in psoriasis. Both CCHCR1 and HAX1 share subcellular co-localization with mitochondria, nuclei and cytoplasmic vesicles as P-bodies. By a series of ribonucleoprotein immunoprecipitation (RIP) assays, we isolated a pool of mRNAs complexed with HAX1 and/or CCHCR1 proteins. Among the mRNAs complexed with both CCHCR1 and HAX1 proteins, there are Vimentin mRNA, previously described to be bound by HAX1, and CAMP/LL37 mRNA, whose gene product is over-expressed in psoriasis.

Alzheimer's Disease: New Concepts on the Role of Autoimmunity and NLRP3 Inflammasome in the Pathogenesis of the Disease

Alzheimer's disease (AD), recognized as the most common neurodegenerative disorder, is clinically characterized by the presence of extracellular beta-amyloid (Aβ) plaques and by intracellular neurofibrillary tau tangles, accompanied by glial activation and neuroinflammation. Increasing evidence suggests that self-misfolded proteins stimulate an immune response mediated by glial cells, inducing the release of inflammatory mediators and the recruitment of peripheral macrophages into the brain, which in turn aggravate AD pathology. The present review aims to update the current knowledge on the role of autoimmunity and neuroinflammation in the pathogenesis of the disease, indicating a new target for therapeutic intervention. We mainly focused on the NLRP3 microglial inflammasome as a critical factor in stimulating innate immune responses, thus sustaining chronic inflammation. Additionally, we discussed the involvement of the NLRP3 inflammasome in the gut-brain axis. Direct targeting of the NLRP3 inflammasome and the associated receptors could be a potential pharmacological strategy since its inhibition would selectively reduce AD neuroinflammation.

Heterozygous Che-1 KO mice show deficiencies in object recognition memory persistence

Transcriptional regulation is a key process in the formation of long-term memories. Che-1 is a protein involved in the regulation of gene transcription that has recently been proved to bind the transcription factor NF-κB, which is known to be involved in many memory-related molecular events. This evidence prompted us to investigate the putative role of Che-1 in memory processes. For this study we newly generated a line of Che-1(+/-) heterozygous mice. Che-1 homozygous KO mouse is lethal during development, but Che-1(+/-) heterozygous mouse is normal in its general anatomical and physiological characteristics. We analyzed the behavioral characteristic and memory performance of Che-1(+/-) mice in two NF-κB dependent types of memory. We found that Che-1(+/-) mice show similar locomotor activity and thigmotactic behavior than wild type (WT) mice in an open field. In a similar way, no differences were found in anxiety-like behavior between Che-1(+/-) and WT mice in an elevated plus maze as well as in fear response in a contextual fear conditioning (CFC) and object exploration in a novel object recognition (NOR) task. No differences were found between WT and Che-1(+/-) mice performance in CFC training and when tested at 24h or 7days after training. Similar performance was found between groups in NOR task, both in training and 24h testing performance. However, we found that object recognition memory persistence at 7days was impaired in Che-1(+/-) heterozygous mice. This is the first evidence showing that Che-1 is involved in memory processes.

eEF1Bγ binds the Che-1 and TP53 gene promoters and their transcripts

Background

We have previously shown that the eukaryotic elongation factor subunit 1B gamma (eEF1Bγ) interacts with the RNA polymerase II (pol II) alpha-like subunit “C” (POLR2C), alone or complexed, in the pol II enzyme. Moreover, we demonstrated that eEF1Bγ binds the promoter region and the 3’ UTR mRNA of the vimentin gene. These events contribute to localize the vimentin transcript and consequentially its translation, promoting a proper mitochondrial network.

Methods

With the intent of identifying additional transcripts that complex with the eEF1Bγ protein, we performed a series of ribonucleoprotein immunoprecipitation (RIP) assays using a mitochondria-enriched heavy membrane (HM) fraction.

Results

Among the eEF1Bγ complexed transcripts, we found the mRNA encoding the Che-1/AATF multifunctional protein. As reported by other research groups, we found the tumor suppressor p53 transcript complexed with the eEF1Bγ protein. Here, we show for the first time that eEF1Bγ binds not only Che-1 and p53 transcripts but also their promoters. Remarkably, we demonstrate that both the Che-1 transcript and its translated product localize also to the mitochondria and that eEF1Bγ depletion strongly perturbs the mitochondrial network and the correct localization of Che-1. In a doxorubicin (Dox)-induced DNA damage assay we show that eEF1Bγ depletion significantly decreases p53 protein accumulation and slightly impacts on Che-1 accumulation. Importantly, Che-1 and p53 proteins are components of the DNA damage response machinery that maintains genome integrity and prevents tumorigenesis.

Conclusions

Our data support the notion that eEF1Bγ, besides its canonical role in translation, is an RNA-binding protein and a key player in cellular stress responses. We suggest for eEF1Bγ a role as primordial transcription/translation factor that links fundamental steps from transcription control to local translation.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0424-x) contains supplementary material, which is available to authorized users.

Pathways Implicated in Tadalafil Amelioration of Duchenne Muscular Dystrophy

Numerous therapeutic approaches for Duchenne and Becker Muscular Dystrophy (DMD and BMD), the most common X-linked muscle degenerative disease, have been proposed. So far, the only one showing a clear beneficial effect is the use of corticosteroids. Recent evidence indicates an improvement of dystrophic cardiac and skeletal muscles in the presence of sustained cGMP levels secondary to a blocking of their degradation by phosphodiesterase five (PDE5). Due to these data, we performed a study to investigate the effect of the specific PDE5 inhibitor, tadalafil, on dystrophic skeletal muscle function. Chronic pharmacological treatment with tadalafil has been carried out in mdx mice. Behavioral and physiological tests, as well as histological and biochemical analyses, confirmed the efficacy of the therapy. We then performed a microarray-based genomic analysis to assess the pattern of gene expression in muscle samples obtained from the different cohorts of animals treated with tadalafil. This scrutiny allowed us to identify several classes of modulated genes. Our results show that PDE5 inhibition can ameliorate dystrophy by acting at different levels. Tadalafil can lead to (1) increased lipid metabolism; (2) a switch towards slow oxidative fibers driven by the up-regulation of PGC-1α; (3) an increased protein synthesis efficiency; (4) a better actin network organization at Z-disk.

SMN affects membrane remodelling and anchoring of the protein synthesis machinery

Disconnection between membrane signalling and actin networks can have catastrophic effects depending on cell size and polarity. The survival motor neuron (SMN) protein is ubiquitously involved in assembly of spliceosomal small nuclear ribonucleoprotein particles. Other SMN functions could, however, affect cellular activities driving asymmetrical cell surface expansions. Genes able to mitigate SMN deficiency operate within pathways in which SMN can act, such as mRNA translation, actin network and endocytosis. Here, we found that SMN accumulates at membrane protrusions during the dynamic rearrangement of the actin filaments. In addition to localization data, we show that SMN interacts with caveolin-1, which mediates anchoring of translation machinery components. Importantly, SMN deficiency depletes the plasma membrane of ribosomes, and this correlates with the failure of fibroblasts to extend membrane protrusions. These findings strongly support a relationship between SMN and membrane dynamics. We propose that SMN could assembly translational platforms associated with and governed by the plasma membrane. This activity could be crucial in cells that have an exacerbated interdependence of membrane remodelling and local protein synthesis.

Novel adeno-associated viral vector delivering the utrophin gene regulator jazz counteracts dystrophic pathology in mdx mice

Over-expression of the dystrophin-related gene utrophin represents a promising therapeutic strategy for Duchenne muscular dystrophy (DMD). The strategy is based on the ability of utrophin to functionally replace defective dystrophin. We developed the artificial zinc finger transcription factor “Jazz” that up-regulates both the human and mouse utrophin promoter. We observed a significant recovery of muscle strength in dystrophic Jazz-transgenic mdx mice. Here we demonstrate the efficacy of an experimental gene therapy based on the systemic delivery of Jazz gene in mdx mice by adeno-associated virus (AAV). AAV serotype 8 was chosen on the basis of its high affinity for skeletal muscle. Muscle-specific expression of the therapeutic Jazz gene was enhanced by adding the muscle α-actin promoter to the AAV vector (mAAV). Injection of mAAV8-Jazz viral preparations into mdx mice resulted in muscle-specific Jazz expression coupled with up-regulation of the utrophin gene. We show a significant recovery from the dystrophic phenotype in mAAV8-Jazz-treated mdx mice. Histological and physiological analysis revealed a reduction of fiber necrosis and inflammatory cell infiltration associated with functional recovery in muscle contractile force. The combination of ZF-ATF technology with the AAV delivery can open a new avenue to obtain a therapeutic strategy for treatment of DMD. J. Cell. Physiol. 229: 1283–1291, 2014. © 2014 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.

Centrosomal Che-1 protein is involved in the regulation of mitosis and DNA damage response by mediating pericentrin (PCNT)-dependent Chk1 protein localization

To combat threats posed by DNA damage, cells have evolved mechanisms, collectively termed DNA damage response (DDR). These mechanisms detect DNA lesions, signal their presence, and promote their repair. Centrosomes integrate G2/M checkpoint control and repair signals in response to genotoxic stress, acting as an efficient control mechanism when G2/M checkpoint function fails and mitosis begins in the presence of damaged DNA. Che-1 is an RNA polymerase II-binding protein involved in the regulation of gene transcription, induction of cell proliferation, and DDR. Here we provide evidence that in addition to its nuclear localization, Che-1 localizes at interphase centrosomes, where it accumulates following DNA damage or spindle poisons. We show that Che-1 depletion generates supernumerary centrosomes, multinucleated cells, and multipolar spindle formation. Notably, Che-1 depletion abolishes the ability of Chk1 to bind pericentrin and to localize at centrosomes, which, in its turn, deregulates the activation of centrosomal cyclin B-Cdk1 and advances entry into mitosis. Our results reinforce the notion that Che-1 plays an important role in DDR and that its contribution seems to be relevant for the spindle assembly checkpoint.

Age-related changes of hippocampal synaptic plasticity in AβPP-null mice are restored by NGF through p75NTR

Amyloid-β protein precursor (AβPP) is a ubiquitous protein found in all cell types, suggesting basic and yet important roles, which still remain to be fully elucidated. Loss of function of AβPP has been linked to abnormal neuronal morphology and synaptic function within the hippocampus and alterations in spatial learning, suggesting a neurotrophic role for this protein. Besides AβPP, nerve growth factor (NGF) and other neurotrophins have also been shown to finely modulate neuronal excitability, synaptic plasticity, and cognitive functions. In addition, recent data support the hypothesis of a functional interconnection between AβPP and NGF pathway. Here, we demonstrated that loss of AβPP function, leading to progressive decrease of choline acetyltransferase expression in the septum, correlates with age-related impairment of long-term potentiation (LTP) in the dentate gyrus. We next addressed whether impaired hippocampal plasticity in AβPP-null mice can be restored upon NGF treatment. Notably, NGF, as well as Pro-NGF, can fully revert LTP deficits in AβPP-null mice through p75NTR and JNK pathway activation. Overall the present study may unveil a new mechanism by which, in the absence of AβPP, NGF treatment may preferentially direct p75-neurotrophin-dependent JNK activation toward regeneration and plasticity in functionally relevant brain circuits.

The eEF1γ subunit contacts RNA polymerase II and binds vimentin promoter region

Here, we show that the eukaryotic translation elongation factor 1 gamma (eEF1γ) physically interacts with the RNA polymerase II (pol II) core subunit 3 (RPB3), both in isolation and in the context of the holo-enzyme. Importantly, eEF1γ has been recently shown to bind Vimentin mRNA. By chromatin immunoprecipitation experiments, we demonstrate, for the first time, that eEF1γ is also physically present on the genomic locus corresponding to the promoter region of human Vimentin gene. The eEF1γ depletion causes the Vimentin protein to be incorrectly compartmentalised and to severely compromise cellular shape and mitochondria localisation. We demonstrate that eEF1γ partially colocalises with the mitochondrial marker Tom20 and that eEF1γ depletion increases mitochondrial superoxide generation as well as the total levels of carbonylated proteins. Finally, we hypothesise that eEF1γ, in addition to its role in translation elongation complex, is involved in regulating Vimentin gene by contacting both pol II and the Vimentin promoter region and then shuttling/nursing the Vimentin mRNA from its gene locus to its appropriate cellular compartment for translation.

Transgenic mice expressing an artificial zinc finger regulator targeting an endogenous gene

Zinc finger (ZF) proteins belonging to the Cys2-His2 class provide a simple and versatile framework to design novel artificial transcription factors (ATFs) targeted to the desired genes. Our work is based on ZF ATFs engineered to up-regulate the expression level of the dystrophin-related gene utrophin in Duchenne muscular dystrophy (DMD). In particular, on the basis of the "recognition code" that defines specific rules between zinc finger primary structure and potential DNA-binding sites we engineered and selected a new family of artificial transcription factors, whose DNA-binding domain consists in a three zinc finger peptide called "Jazz." Jazz protein binds specifically the 9 bp DNA sequence (5(')-GCT-GCT-GCG-3(')) present in the promoter region of both the human and mouse utrophin gene. We generated a transgenic mouse expressing Jazz protein fused to the strong transcriptional activation domain VP16 and under the control of the muscle specific promoter of the myosin light chain gene. Vp16-Jazz mice display a strong up-regulation of the utrophin at both mRNA and protein levels. To our knowledge, this represents the first example of a transgenic mouse expressing an artificial gene coding for a zinc finger-based transcription factor.

The artificial gene Jazz, a transcriptional regulator of utrophin, corrects the dystrophic pathology in mdx mice

The absence of the cytoskeletal protein dystrophin results in Duchenne muscular dystrophy (DMD). The utrophin protein is the best candidate for dystrophin replacement in DMD patients. To obtain therapeutic levels of utrophin expression in dystrophic muscle, we developed an alternative strategy based on the use of artificial zinc finger transcription factors (ZF ATFs). The ZF ATF 'Jazz' was recently engineered and tested in vivo by generating a transgenic mouse specifically expressing Jazz at the muscular level. To validate the ZF ATF technology for DMD treatment we generated a second mouse model by crossing Jazz-transgenic mice with dystrophin-deficient mdx mice. Here, we show that the artificial Jazz protein restores sarcolemmal integrity and prevents the development of the dystrophic disease in mdx mice. This exclusive animal model establishes the notion that utrophin-based therapy for DMD can be efficiently developed using ZF ATF technology and candidates Jazz as a novel therapeutic molecule for DMD therapy.

Novel activation domain derived from Che-1 cofactor coupled with the artificial protein Jazz drives utrophin upregulation

Our aim is to upregulate the expression level of the dystrophin related gene utrophin in Duchenne muscular dystrophy, thus complementing the lack of dystrophin functions. To this end, we have engineered synthetic zinc finger based transcription factors. We have previously shown that the artificial three-zinc finger protein named Jazz fused with the Vp16 activation domain, is able to bind utrophin promoter A and to increase the endogenous level of utrophin in transgenic mice. Here, we report on an innovative artificial protein, named CJ7, that consists of Jazz DNA binding domain fused to a novel activation domain derived from the regulatory multivalent adaptor protein Che-1/AATF. This transcriptional activation domain is 100 amino acids in size and it is very powerful as compared to the Vp16 activation domain. We show that CJ7 protein efficiently promotes transcription and accumulation of the acetylated form of histone H3 on the genomic utrophin promoter locus.

Delayed internalization and lack of recycling in a beta2-adrenergic receptor fused to the G protein alpha-subunit

Background

Chimeric proteins obtained by the fusion of a G protein-coupled receptor (GPCR) sequence to the N-terminus of the G protein α-subunit have been extensively used to investigate several aspects of GPCR signalling. Although both the receptor and the G protein generally maintain a fully functional state in such polypeptides, original observations made using a chimera between the β₂-adrenergic receptor (β₂AR) and Gα_s indicated that the fusion to the α-subunit resulted in a marked reduction of receptor desensitization and down-regulation. To further investigate this phenomenon, we have compared the rates of internalization and recycling between wild-type and Gα_s-fused β₂AR.

Results

The rate of agonist-induced internalization, measured as the disappearance of cell surface immunofluorescence in HEK293 cells permanently expressing N-terminus tagged receptors, was reduced three-fold by receptor-G protein fusion. However, both fused and non-fused receptors translocated to the same endocytic compartment, as determined by dual-label confocal analysis of cells co-expressing both proteins and transferrin co-localization.

Receptor recycling, determined as the reversion of surface immunofluorescence following the addition of antagonist to cells that were previously exposed to agonist, markedly differed between wild-type and fused receptors. While most of the internalized β₂AR returned rapidly to the plasma membrane, β₂AR-Gα_s did not recycle, and the observed slow recovery for the fusion protein immunofluorescence was entirely accounted for by protein synthesis.

Conclusion

The covalent linkage between β₂AR and Gα_s does not appear to alter the initial endocytic translocation of the two proteins, although there is reduced efficiency. It does, however, completely disrupt the process of receptor and G protein recycling. We conclude that the physical separation between receptor and Gα is not necessary for the transit to early endosomes, but is an essential requirement for the correct post-endocytic sorting and recycling of the two proteins.

The artificial 4-zinc-finger protein Bagly binds human utrophin promoter A at the endogenous chromosomal site and activates transcription

Our aim is to upregulate the expression of the dystrophin-related gene utrophin in Duchenne muscular dystrophy, in this way complementing the lack of dystrophin function. To achieve utrophin upregulation, we designed and engineered synthetic zinc-finger based transcription factors. We have previously shown that the artificial 3-zinc-finger protein Jazz, fused with the appropriate effector domain, is able to drive the transcription of a test gene from utrophin promoter A. Here we report a novel artificial 4-zinc-finger protein, Bagly, which binds with optimized affinity-specificity to a 12 bp DNA target sequence that is internal to human utrophin promoter A. Bagly was generated adding to Jazz protein an extra-fourth zinc finger, derived from transcription factor YY1. Importantly, the Bagly DNA target sequence is statistically present in the human genome only 210 times, about 60 fewer times than the 9 bp Jazz DNA target sequence. Thanks to its additional zinc-finger domain, Bagly protein shows enhanced transcriptional activity. Moreover, we demonstrated Bagly's effective access and binding to active chromatin in the chromosomal context and its ability to upregulate endogenous utrophin.

Utrophin up-regulation by an artificial transcription factor in transgenic mice

Duchenne Muscular Dystrophy (DMD) is a severe muscle degenerative disease, due to absence of dystrophin. There is currently no effective treatment for DMD. Our aim is to up-regulate the expression level of the dystrophin related gene utrophin in DMD, complementing in this way the lack of dystrophin functions. To this end we designed and engineered several synthetic zinc finger based transcription factors. In particular, we have previously shown that the artificial three zinc finger protein named Jazz, fused with the appropriate effector domain, is able to drive the transcription of a test gene from the utrophin promoter “A”. Here we report on the characterization of Vp16-Jazz-transgenic mice that specifically over-express the utrophin gene at the muscular level. A Chromatin Immunoprecipitation assay (ChIP) demonstrated the effective access/binding of the Jazz protein to active chromatin in mouse muscle and Vp16-Jazz was shown to be able to up-regulate endogenous utrophin gene expression by immunohistochemistry, western blot analyses and real-time PCR. To our knowledge, this is the first example of a transgenic mouse expressing an artificial gene coding for a zinc finger based transcription factor. The achievement of Vp16-Jazz transgenic mice validates the strategy of transcriptional targeting of endogenous genes and could represent an exclusive animal model for use in drug discovery and therapeutics.

NRAGE associates with the anti-apoptotic factor Che-1 and regulates its degradation to induce cell death

Neurotrophin receptor-interacting MAGE homolog (NRAGE) has been recently identified as a cell-death inducer, involved in molecular events driving cells through apoptotic networks during neuronal development. Recently, we have focused on the functional role of Che-1, also known as apoptosis-antagonizing transcription factor (AATF), a protein involved in cell cycle control and gene transcription. Increasing evidence suggests that Che-1 is involved in apoptotic signalling in neural tissues. In cortical neurons Che-1 exhibits an anti-apoptotic activity, protecting cells from neuronal damage induced by amyloid beta-peptide. Here, we report that Che-1 interacts with NRAGE and that an EGFP-NRAGE fusion protein inhibits nuclear localization of Che-1, by sequestering it within the cytoplasmic compartment. Furthermore, NRAGE overexpression downregulates endogenous Che-1 by targeting it for proteasome-dependent degradation. Finally, we propose that Che-1 is a functional antagonist of NRAGE, because its overexpression completely reverts NRAGE-induced cell-death.

Pressure overload causes cardiac hypertrophy in β1-adrenergic and β2-adrenergic receptor double knockout mice

OBJECTIVE

Cardiac hypertrophy arises as an adaptive response to increased afterload. Studies in knockout mice have shown that catecholamines, but not alpha1-adrenergic receptors, are necessary for such an adaptation to occur. However, whether beta-adrenergic receptors are critical for the development of cardiac hypertrophy in response to pressure overload is not known at this time.

METHODS AND RESULTS

Pressure overload was induced by transverse aortic banding in beta1-adrenergic and beta2-adrenergic receptor double knockout (DbetaKO) mice, in which the predominant cardiac beta-adrenergic receptor subtypes are lacking. Chronic pressure overload for 4 weeks induced cardiac hypertrophy in both DbetaKO and wild-type mice. There were no significant differences between banded mice in left ventricular weight to body weight ratio, in the left ventricular wall thickness, in the cardiomyocyte size or in the expression levels of the load-sensitive cardiac genes such as ANF and beta-MHC. Additionally, the left ventricular systolic pressure, an index of afterload, and cardiac contractility, evaluated as dp/dtmax, the maximal slope of systolic pressure increment, and Ees, end-systolic elastance, were increased at a similar level in both wild-type and DbetaKO banded mice, and were significantly greater than in sham controls.

CONCLUSION

Despite chronic activation of the cardiac beta-adrenergic system being sufficient to induce a pathological hypertrophy, we show that beta1-adrenergic and beta2-adrenergic receptors are not an obligatory component of the signaling pathway that links the increased afterload to the development of cardiac hypertrophy.

RNA Polymerase II subunit 3 is retained in the cytoplasm by its interaction with HCR, the psoriasis vulgaris candidate gene product

Here, we show that the subcellular localization of α-like RNA polymerase II core subunit 3 (RPB3) is regulated during muscle differentiation. We have recently demonstrated that the expression of RPB3 is regulated during muscle differentiation and that, inside RNA polymerase II (RNAP II), it is directly involved in contacting regulatory proteins such as the myogenic transcription factor Myogenin and activating transcription factor ATF4. We show for the first time, that RPB3, in addition to its presence and role inside the RNAP II core enzyme, accumulates in the cytoplasm of cycling myogenic cells and migrates to the nucleus upon induction of the differentiation program. Furthermore, using human RPB3 as bait in a yeast two-hybrid system, we have isolated a novel RPB3 cytoplasmic interacting protein, HCR. HCR, previously identified as α-helix coiled-coil rod homologue, is one of the psoriasis vulgaris (PV) candidate genes. In cycling myogenic C2C7 cells, we show that the RPB3 protein directly interacts with HCR within the cytoplasm. Finally, knocking down HCR expression by RNA interference, we demonstrate that HCR acts as cytoplasmic docking site for RPB3.

Possible steps required in the internalization of nude Epstein-Barr virus

The hypothesis proposed is that the internalization of nude EBV by Raji cells-a CR2-positive line-involves a multi-step mechanism. Our data also indicate that Raji cells do not acquire the ability to kill EBV until after the virions attach to the membrane.

CR2 units of CR2 complexes are possibly associated with nucleophilic agents through reactive covalent links

The human complement receptor type 2 (CR2/CD21), a transmembrane glycoprotein, associates with a variety of surface antigens and proteins in the cell membrane. We examined the possibilities that the CR2 units of CR2 complexes are associated through internal covalent links reactive with nucleophilic agents, e.g. H(2)O or methylamine, and that CR2-positive cells process anti-CR2 monoclonal antibodies (MoAbs). Data from immunoblotting and cytofluorimetry with CR2-binding site-specific MoAbs show that: (i) CR2-positive Raji cells release soluble CR2 isoforms into the medium when incubated in phosphate buffered saline; (ii) despite affecting the detection of one soluble CR2 isoform, methylamine treatment of soluble CR2 allows the detection of another of its isoforms; (iii) limited pre-treatment of cells with methylamine reveals a more heterogeneous CR2-positive cell population or enhances the detection of CR2; (iv) cell treatment with CR2-binding site-specific MoAbs enhances the detection of CR2 isoform(s). The data suggest that CR2 is shed mainly as a soluble CR2 complex, in which the CR2 units link covalently and react with nucleophilic agents. Raji cells may process bound fragments (145 kDa) that are recognised by and become bound by anti-CR2 MoAb.