The outbreak of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): a review of the current global status

There is currently an ongoing worldwide pandemic of a novel virus belonging to the family of Coronaviruses (CoVs) which are large, enveloped, plus-stranded RNA viruses. Coronaviruses belong to the order of Nidovirales, family of Coronavirinae and are divided into four genera: alphacoronavirus, betacoronavirus, gammacoronavirus and deltacoronavirus. CoVs cause diseases in a wide variety of birds and mammals and have been found in humans since 1960. To date, seven human CoVs were identified including the alpha-CoVs HCoVs-NL63 and HCoVs-229E and the beta-CoVs HCoVs-OC43, HCoVs-HKU1, the severe acute respiratory syndrome-CoV (SARS-CoV), the Middle East respiratory syndrome-CoV (MERS-CoV) and the novel virus that first appeared in December 2019 in Wuhan, China, and rapidly spread to 213 countries as of the writing this paper. It was officially named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by the international committee on taxonomy of viruses (ICTV) and the disease's name is COVID-19 for coronavirus disease 2019. SARS-CoV-2 is very contagious and is capable of spreading from human to human. Infection routes include droplet and contact, and aerosol transmission is currently under investigation. It is associated with a respiratory illness that may cause severe pneumonia and acute respiratory distress syndrome (ARDS). SARS-CoV-2 became an emergency of international concern. As of July 12, 2020, the virus has been responsible for 12,698,995 confirmed cases and 564,924 deaths worldwide and the number is still increasing. Up until now, no specific treatment has yet been proven effective against SARS-CoV-2. Since the beginning of this outbreak, several interesting papers on SARS-CoV-2 and COVID-19 have been published to report on the phylogenetic evolution, epidemiology, pathogenesis, transmission as well as clinical characteristics of COVID-19 and possible treatments agents. This paper is a systematic review of the available literature on SARS-CoV-2. It was performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and aims to help readers access the latest knowledge surrounding this new infectious disease and to provide a reference for future studies

Expression signature of the Leigh syndrome French-Canadian type

As a result of a founder effect, a Leigh syndrome variant called Leigh syndrome, French-Canadian type (LSFC, MIM / 220,111) is more frequent in Saguenay–Lac-Saint-Jean (SLSJ), a geographically isolated region on northeastern Quebec, Canada. LSFC is a rare autosomal recessive mitochondrial neurodegenerative disorder due to damage in mitochondrial energy production. LSFC is caused by pathogenic variants in the nuclear gene leucine-rich pentatricopeptide repeat-containing (LRPPRC). Despite progress understanding the molecular mode of action of LRPPRC gene, there is no treatment for this disease. The present study aims to identify the biological pathways altered in the LSFC disorder through microarray-based transcriptomic profile analysis of twelve LSFC cell lines compared to twelve healthy ones, followed by gene ontology (GO) and pathway analyses. A set of 84 significantly differentially expressed genes were obtained (p ≥ 0.05; Fold change (Flc) ≥ 1.5). 45 genes were more expressed (53.57%) in LSFC cell lines compared to controls and 39 (46.43%) had lower expression levels. Gene ontology analysis highlighted altered expression of genes involved in the mitochondrial respiratory chain and energy production, glucose and lipids metabolism, oncogenesis, inflammation and immune response, cell growth and apoptosis, transcription, and signal transduction. Considering the metabolic nature of LSFC disease, genes included in the mitochondrial respiratory chain and energy production cluster stood out as the most important ones to be involved in LSFC mitochondrial disorder. In addition, the protein-protein interaction network indicated a strong interaction between the genes included in this cluster. The mitochondrial gene NDUFA4L2 (NADH dehydrogenase [ubiquinone] 1 alpha subcomplex, 4-like 2), with higher expression in LSFC cells, represents a target for functional studies to explain the role of this gene in LSFC disease. This work provides, for the first time, the LSFC gene expression profile in fibroblasts isolated from affected individuals. This represents a valuable resource to understand the pathogenic basis and consequences of LRPPRC dysfunction

Generation of a human induced pluripotent stem cell line (UQACi001-A) from a severe epidermolysis bullosa simplex patient with the heterozygous mutation p.R125S in the KRT14 gene

We have generated UQACi001-A, a new induced pluripotent stem cell (iPSC) line derived from skin fibroblasts of a male patient with the generalized severe epidermolysis bullosa simplex phenotype (EBS-gen sev) and carrying the keratin 14 (K14) R125S mutation. Fibroblasts were reprogrammed using non-integrating Sendai virus vectors. The iPSC line displayed normal molecular karyotype, expressed pluripotency markers, is capable of differentiating into three embryonic germ layers and is genetically identical to the originating parental fibroblasts. The established iPSC model provides a valuable resource for studying the rare disease of epidermolysis bullosa simplex and developing new therapies as DNA editing by CRISPR/Cas9 technology

Generation of two induced pluripotent stem cell lines (UQACi002-A and UQACi005-A) from two patients with KRT14 epidermolysis bullosa simplex mutations

More than 107 pathogenic variations were identified in Keratin 14 gene (KRT14) in patients affected by epidermolysis bullosa simplex (EBS), a rare skin disease with still no curative treatment. Disease models as human induced pluripotent stem cells (hiPSCs) are promising tool for further advance the knowledge about this disorder and accelerate therapies development. Here, two hiPSC lines were reprogrammed from skin fibroblasts of two EBS patients carrying mutations within KRT14 by using CytoTune®Sendai virus. These iPSCs display pluripotent cell morphology, pluripotent markers expression, and the capability to differentiate into the three germ layers

Generation of three induced pluripotent stem cell lines (UQACi003-A, UQACi004-A, and UQACi006-A) from three patients with KRT5 epidermolysis bullosa simplex mutations

Heterozygous mutations within Keratin 5 (KRT5) are common genetic causes of epidermolysis bullosa simplex (EBS), a skin fragility disorder characterized by blisters, which appear after minor trauma. Using CytoTune®Sendai virus, we generated three human induced pluripotent stem cell (iPSC) lines from three EBS patients carrying respectively the single heterozygous mutations in KRT5, c.449 T > C, c.980 T > C, and c.608 T > C. All lines display normal karyotype, expressed high levels of pluripotent markers, and can differentiate into derivatives of the three germ layers. These iPSCs are helpful for a better understanding of the EBS pathogenesis and developing novel therapeutic approaches

Genetic burden linked to founder effects in Saguenay–Lac-Saint-Jean illustrates the importance of genetic screening test availability

The Saguenay–Lac-Saint-Jean (SLSJ) region located in the province of Quebec was settled in the 19th century by pioneers issued from successive migration waves starting in France in the 17th century and continuing within Quebec until the beginning of the 20th century. The genetic structure of the SLSJ population is considered to be the product of a triple founder effect and is characterised by a higher prevalence of some rare genetic diseases. Several studies were performed to elucidate the historical, demographic and genetic background of current SLSJ inhabitants to assess the origins of these rare disorders and their distribution in the population. Thanks to the development of new sequencing technologies, the genes and the variants responsible for the most prevalent conditions were identified. Combined with other resources such as the BALSAC population database, identifying the causal genes and the pathogenic variants allowed to assess the impacts of some of these founder mutations on the population health and to design precision medicine public health strategies based on carrier testing. Furthermore, it stimulated the establishment of many public programmes. We report here a review and an update of a subset of inherited disorders and founder mutations in the SLSJ region. Data were collected from published scientific sources. This work expands the knowledge about the current frequencies of these rare disorders, the frequencies of other rare genetic diseases in this population, the relevance of the carrier tests offered to the population, as well as the current available treatments and research about future therapeutic avenues for these inherited disorders

Gene expression analysis of epidermolysis bullosa simplex with mottled pigmentation

Epidermolysis bullosa simplex with mottled pigmentation (EBS-MP) is a subtype of epidermolysis bullosa simplex first reported in 1979. The disease has its onset in early childhood and manifests with either much localized skin blistering, resembling the Weber-Cockayne subtype of EBS, or with more extensive bulla formation as seen in the Koebner subtype of EBS. Associated features include palmoplantar keratoderma and reticular hyperpigmentation unrelated to the blistering

Reduction in keratin aggregates in epidermolysis bullosa simplex keratinocytes after pretreatment with trimethylamine N-oxide

Epidermolysis bullosa simplex (EBS) is a dominantly inherited skin disease caused by mutations in the keratin 5 (KRT5) or KRT14 genes 1. Some reports suggested that fever and/or hot weather may exacerbate EBS phenotype 2. Effective EBS therapies are still lacking. Molecular chaperones are proteins whose main function is to promote the correct folding of polypeptides (s1). Molecules such as trimethylamine N-oxide (TMAO) and sodium 4-phenylbutyrate (4-PBA) act as chemical chaperones (s2) with protein folding and stabilization activities (s3, s4, s5). Treatment of affected epidermal cells by chemical chaperones to correct the misfolded and aggregated keratins that characterize EBS seems a viable therapeutic option 3. Furthermore, the type I keratins K16 and K17 polymerize with K5, and upregulation of these proteins could replace the mutant K14 in the heterodimer and improve disease pathology (s6). Hence, chemical chaperones which can reduce keratin aggregates formation and upregulate K16 and K17 in EBS-affected cells would be ideal therapeutic candidates for EBS

The first Mal de Meleda case in Libya: identification of a SLURP1 mutation

Mal de Meleda (MDM) is a rare autosomal recessive palmoplantar keratoderma (PPK). It is characterized by erythema and transgressive PPK that appears soon after birth and progressively extends to the dorsal aspects of the hands. MDM was originally described in patients from Mljet/Meleda almost 200 years ago. Since then, patients with MDM were also described in more widespread regions, including the Mediterranean area, and Middle and East Asia. MDM is caused by mutations in the SLURP1 gene encoding the SLURP1 protein. SLURP1 enhances the function of the nicotinic acetylcholine receptor a7 in epidermal keratinocytes eliciting proapoptotic activity and differentiation. To date, only 14 SLURP1 mutations were described in the literature. The p.G86R loss-of-function mutation has been reported in patients from Taiwan, Palestine, Pakistan, Korea, and Turkey. In this report, we further describe this variation in a family of Libyan descent (North Africa), which would have important consequences for genetic counseling to individuals of Libyan origin whose relatives are MDM affected