GENETIC CHAPERONOPATHIES ASSOCIATED WITH GROUP II CHAPERONIN VARIANTS

Genetic chaperonopathies manifest themselves from very early in life. Chaperonopathies related to neurodegenerative disorders discussed in “Introduction” section are a heterogeneous group of disorders which affect one or more of the various physiological systems, for example, the nervous system. This heterogeneity is due, in particular, to the not fully known molecular activity, which every single molecular chaperone has within a specific tissue. My general questions about them were 1) why a mutation on a molecular chaperone that is expressed by most, if not all cytotypes, seems to affect the functioning of a single physiological system? 2) why do different mutations on the same molecular chaperone cause apparently different pathologies especially in terms of clinical manifestations? This heterogeneity limits the research approach on diseases, which now is conducted towards every single mutation without being able to generalize a unique molecular process. I spent the first 18 months of my Ph.D. project at the SBARRO Department of Temple University in Philadelphia to study the V98I mutation on chaperone Hsp60 causing hereditary spastic paraplegia (SPG13). For a better understanding of the associated diseases, it would be highly beneficial to examine the impact of mutant chaperone genes during development, starting with fertilization and proceeding throughout the entire ontogenetic process. Zebrafish is amenable to such embryonal analysis as well as studies during adulthood. In addition, the zebrafish genome contains a wide range of genes encoding proteins similar to those that form the chaperoning system in humans. Due to the very complex roles played by Hsp60 in cell and tissue homeostasis, the gene is highly conserved during evolution. Nucleotide and amino acid sequences of Hsp60 in zebrafish have 88% of identity with its human orthologous. The first aim of my research was the establishment of a zebrafish model as an innovative approach for the study of the molecular basis of SPG13 and define the role of missense mutations V98I. In the last 18 months of my Ph.D. project, I was at the BIND Department of the University of Palermo and I had the possibility to study a new mutation that occurred in subunit number 5 of CCT complex. This mutation was found in a pediatric patient who is now being treated by the Department Of Sciences For The Promotion Of Health And Childhood "G. D'Alessandro" at the University of Palermo. Thus, I focused my attention on this novel variant. The main aims were 1) understanding, with the help of bioinformatics software, the type of mutation and if it causes some alteration of chaperonin molecular anatomy; 2) define the morphological changes caused by the mutation in skeletal muscle tissue

Imaging features of uterine and ovarian fibromatosis in Nevoid Basal Cell Carcinoma Syndrome

Gorlin-Goltz Syndrome also known as Nevoid Basal Cell Carcinoma Syndrome is an autosomal dominant multisystem disorder. It is characterized by basal cell carcinomas, odontogenic keratocysts, skeletal abnormalities and in a minority of female patients bilateral calcified ovarian fibromas. It is challenging to radiologically assess ovarian fibromas as they have similar imaging patterns to some malignant ovarian lesions. However, it is vitally important to differentiate between benign and malignant lesions to determine patients' suitability for fertility-sparing surgery. This report describes a case of a 25 year-old patient with Gorlin-Goltz Syndrome and bilateral ovarian fibromas

Histopathology of Skeletal Muscle in a Distal Motor Neuropathy Associated with a Mutant CCT5 Subunit: Clues for Future Developments to Improve Differential Diagnosis and Personalized Therapy

Genetic chaperonopathies are rare but, because of misdiagnosis, there are probably more cases than those that are recorded in the literature and databases. This occurs because practitioners are generally unaware of the existence and/or the symptoms and signs of chaperonopathies. It is necessary to educate the medical community about these diseases and, with research, to unveil their mechanisms. The structure and functions of various chaperones in vitro have been studied, but information on the impact of mutant chaperones in humans, in vivo, is scarce. Here, we present a succinct review of the most salient abnormalities of skeletal muscle, based on our earlier report of a patient who carried a mutation in the chaperonin CCT5 subunit and suffered from a distal motor neuropathy of early onset. We discuss our results in relation to the very few other published pertinent reports we were able to find. A complex picture of multiple muscle-tissue abnormalities was evident, with signs of atrophy, apoptosis, and abnormally low levels and atypical distribution patterns of some components of muscle and the chaperone system. In-silico analysis predicts that the mutation affects CCT5 in a way that could interfere with the recognition and handling of substrate. Thus, it is possible that some of the abnormalities are the direct consequence of defective chaperoning, but others may be indirectly related to defective chaperoning or caused by other different pathogenic pathways. Biochemical, and molecular biologic and genetic analyses should now help in understanding the mechanisms underpinning the histologic abnormalities and, thus, provide clues to facilitate diagnosis and guide the development of therapeutic tools

Possible A2E Mutagenic Effects on RPE Mitochondrial DNA from Innovative RNA-Seq Bioinformatics Pipeline

Mitochondria are subject to continuous oxidative stress stimuli that, over time, can impair their genome and lead to several pathologies, like retinal degenerations. Our main purpose was the identification of mtDNA variants that might be induced by intense oxidative stress determined by N-retinylidene-N-retinylethanolamine (A2E), together with molecular pathways involving the genes carrying them, possibly linked to retinal degeneration. We performed a variant analysis comparison between transcriptome profiles of human retinal pigment epithelial (RPE) cells exposed to A2E and untreated ones, hypothesizing that it might act as a mutagenic compound towards mtDNA. To optimize analysis, we proposed an integrated approach that foresaw the complementary use of the most recent algorithms applied to mtDNA data, characterized by a mixed output coming from several tools and databases. An increased number of variants emerged following treatment. Variants mainly occurred within mtDNA coding sequences, corresponding with either the polypeptide-encoding genes or the RNA. Time-dependent impairments foresaw the involvement of all oxidative phosphorylation complexes, suggesting a serious damage to adenosine triphosphate (ATP) biosynthesis, that can result in cell death. The obtained results could be incorporated into clinical diagnostic settings, as they are hypothesized to modulate the phenotypic expression of mtDNA pathogenic variants, drastically improving the field of precision molecular medicine

Air Pollution: Role of Extracellular Vesicles-Derived Non-Coding RNAs in Environmental Stress Response

Air pollution has increased over the years, causing a negative impact on society due to the many health-related problems it can contribute to. Although the type and extent of air pollutants are known, the molecular mechanisms underlying the induction of negative effects on the human body remain unclear. Emerging evidence suggests the crucial involvement of different molecular mediators in inflammation and oxidative stress in air pollution-induced disorders. Among these, non-coding RNAs (ncRNAs) carried by extracellular vesicles (EVs) may play an essential role in gene regulation of the cell stress response in pollutant-induced multiorgan disorders. This review highlights EV-transported ncRNAs’ roles in physiological and pathological conditions, such as the development of cancer and respiratory, neurodegenerative, and cardiovascular diseases following exposure to various environmental stressors

Sudden Unexpected Deaths and Vaccinations during the First Two Years of Life in Italy: A Case Series Study

Background The signal of an association between vaccination in the second year of life with a hexavalent vaccine and sudden unexpected deaths (SUD) in the two days following vaccination was reported in Germany in 2003. A study to establish whether the immunisation with hexavalent vaccines increased the short term risk of SUD in infants was conducted in Italy. Methodology/Principal Findings The reference population comprises around 3 million infants vaccinated in Italy in the study period 1999–2004 (1.5 million received hexavalent vaccines). Events of SUD in infants aged 1–23 months were identified through the death certificates. Vaccination history was retrieved from immunisation registries. Association between immunisation and death was assessed adopting a case series design focusing on the risk periods 0–1, 0–7, and 0–14 days after immunisation. Among the 604 infants who died of SUD, 244 (40%) had received at least one vaccination. Four deaths occurred within two days from vaccination with the hexavalent vaccines (RR = 1.5; 95% CI 0.6 to 4.2). The RRs for the risk periods 0–7 and 0–14 were 2.0 (95% CI 1.2 to 3.5) and 1.5 (95% CI 0.9 to 2.4). The increased risk was limited to the first dose (RR = 2.2; 95% CI 1.1 to 4.4), whereas no increase was observed for the second and third doses combined. Conclusions The RRs of SUD for any vaccines and any risk periods, even when greater than 1, were almost an order of magnitude lower than the estimates in Germany. The limited increase in RRs found in Italy appears confined to the first dose and may be partly explained by a residual uncontrolled confounding effect of age

The Neurochaperonopathies: Anomalies of the Chaperone System with Pathogenic Effects in Neurodegenerative and Neuromuscular Disorders

The chaperone (or chaperoning) system (CS) constitutes molecular chaperones, co-chaperones, and chaperone co-factors, interactors and receptors, and its canonical role is protein quality control. A malfunction of the CS may cause diseases, known as the chaperonopathies. These are caused by qualitatively and/or quantitatively abnormal molecular chaperones. Since the CS is ubiquitous, chaperonopathies are systemic, affecting various tissues and organs, playing an etiologic-pathogenic role in diverse conditions. In this review, we focus on chaperonopathies involved in the pathogenic mechanisms of diseases of the central and peripheral nervous systems: the neurochaperonopathies (NCPs). Genetic NCPs are linked to pathogenic variants of chaperone genes encoding, for example, the small Hsp, Hsp10, Hsp40, Hsp60, and CCT-BBS (chaperonin-containing TCP-1- Bardet–Biedl syndrome) chaperones. Instead, the acquired NCPs are associated with malfunctional chaperones, such as Hsp70, Hsp90, and VCP/p97 with aberrant post-translational modifications. Awareness of the chaperonopathies as the underlying primary or secondary causes of disease will improve diagnosis and patient management and open the possibility of investigating and developing chaperonotherapy, namely treatment with the abnormal chaperone as the main target. Positive chaperonotherapy would apply in chaperonopathies by defect, i.e., chaperone insufficiency, and consist of chaperone replacement or boosting, whereas negative chaperonotherapy would be pertinent when a chaperone actively participates in the initiation and progression of the disease and must be blocked and eliminated

Anatomy and physiology of peripheral and central vestibular system

The vestibular system includes different anatomical structures and physiological pathways. In the first part of this chapter, we will briefly introduce the main anatomical constituents, i.e., vestibule, semicircular canals, vestibular ganglia and nerve, vestibular nuclei, flocculo-nodular lobe of cerebellum and other structures in the brain stem. In the second parts, we will discuss the pathways generated by signals transduced by vestibular structures. Briefly, the bony labyrinth is lined with the endolymph-containing membranous labyrinth, showing two chambers (utricle and saccule) and three semicircular canals (horizontal, anterior, and posterior). Each canal contains a receptor organ called crista ampullaris, whereas receptor organs of both utriculus and sacculus are called otolithic macula. All the information transduced by receptors travels through the vestibular nerve fibers and reachs the vestibular nuclei in the pons and medulla oblongata. The axons originated here supply various CNS areas, e.g., the spinal cord, oculogyric nuclei, the reticular formation, and the cerebellum. Vestibular receptors respond to accelerations of the head in space, providing direct information about its rotations (receptors of semicircular canals), orientation with respect to gravity and linear movements (receptors of otolithic maculae). Semicircular canals are excited by rotational accelerations, converted into rotational velocity signals by the mechanical structure of the canal. Each labyrinth is excited by ipsilateral head rotation, both labyrinths are excited by purely forward or backward rotation. The utricular macula lies horizontally, whereas the saccular macula is placed vertically. When the head is still and held erect with respect to gravity, the utricular macula is not stimulated, and tilts from the erect posture will excite utricular afferents. Conversely, the saccular macula is strongly stimulated when the head is erect, and little or not when the head is lying on either side. Vestibular signals (ipsilateral rotational head velocity, head tilt, or equivalent linear acceleration) assist balance: the vestibulocervical reflex excites neck muscles via the medial vestibulospinal tract to oppose head tilt, and vestibulospinal reflexes excite ipsilateral limb extensors via the lateral vestibulospinal tract to oppose body tilt