The History, Efficacy, and Safety of Potential Therapeutics: A Narrative Overview of the Complex Life of COVID-19.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic posed a serious public health concern and started a race against time for researchers to discover an effective and safe therapy for coronavirus disease 2019 (COVID-19), the disease caused by SARS-CoV-2. This review aims to describe the history, efficacy, and safety of five potential therapeutics for COVID-19, remdesivir, favipiravir, hydroxychloroquine, tocilizumab, and convalescent plasma. A literature review was conducted through October 2020 to identify published studies evaluating the efficacy and safety of these five potential therapeutics. Clinical improvement was used to assess the efficacy, while reported withdrawals from study participation and adverse events were used to evaluate the safety. In total, 95 clinical studies (6 interventional and 89 observational studies) were obtained, of which 42 were included in this review. The evaluation of the efficacy and safety profiles is challenging due to the limitations of the clinical studies on one hand, and the limited number of randomized controlled trials (RCTs) on the other. Moreover, there was insufficient evidence to support repurposing remdesivir, favipiravir, and tocilizumab for COVID-19.

COQ8A and MED25 Mutations in a Child with Intellectual Disability, Microcephaly, Seizures, and Spastic Ataxia: Synergistic Effect of Digenic Variants?

We report on a girl, born to first-cousin Lebanese parents, with severe intellectual disability, congenital hip luxation, cardiac malformation, short stature, facial dysmorphic features including microcephaly, sparse hair, bilateral epicanthal folds, ataxia, seizures, and elevated lactate and pyruvate levels in serum. Whole exome sequencing was carried out on the patient's DNA. Potentially causal homozygous variants in the MED25 (p.Ile173Thr) and COQ8A (p.Arg512Trp) genes were found. The potential pathogenicity of these variants, and the possibility that the 2 variants could synergistically act to produce the phenotype reported, is discussed.

The potential of SNP-based PCR-RFLP capillary electrophoresis analysis to authenticate and detect admixtures of Mediterranean olive oils.

Authentication and traceability of extra virgin olive oil is a challenging research task due to the complexity of fraudulent practices. In this context, the monovarietal olive oils of Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) require new tests and cutting edge analytical technologies to detect mislabeling and misleading origin. Toward this direction, DNA-based technologies could serve as a complementary to the analytical techniques assay. Single nucleotide polymorphisms are ideal molecular markers since they require short PCR analytical targets which are a prerequisite for forensic applications in olive oil sector. In the present study, a small number of polymorphic SNPs were used with an SNP-based PCR-RFLP capillary electrophoresis platform to discriminate six out of 13 monovarietal olive oils of Mediterranean origin from three different countries, Greece, Tunisia, and Lebanon. Moreover, the high sensitivity of capillary electrophoresis in combination with the DNA extraction protocol lowered the limit of detection to 10% in an admixture of Tsounati in a Koroneiki olive oil matrix.

Transgenic expression of human INS gene in Ins1/Ins2 double knockout mice leads to insulin underproduction and diabetes in some male mice.

We have generated transgenic mouse lines expressing exclusively a human INS transgene on an Ins1/Ins2 double knockout (mIKO) background. The transgene expression was driven by either a 4000 bp or a 353 bp promoter. These transgenic lines, designated mIKO:INS4000 and mIKO:INS353, were viable and fertile. Determination of the amounts of insulin transcripts and total pancreatic insulin content revealed relative insulin underproduction in both lines, from birth to adulthood. Total pancreatic insulin stores in mIKO:INS4000 and mIKO:INS353 mice represented only about 50% and 27%, respectively, as compared to wild-type mice. Morphometric analysis of pancreas did not show any compensatory beta-cell hyperplasia. The majority of animals in both lines remained normoglycemic throughout their lives. Nevertheless, glucose tolerance tests revealed glucose intolerance in nearly half of mIKO:INS4000 male mice, likely due to impaired insulin secretion detected in those animals. In addition, a small fraction (2-4%) of male mice in both lines spontaneously developed diabetes with very distinct pathophysiological features. Diabetes was never seen in female animals. The diabetes developed by mIKO:INS353 mice was rapidly lethal, accompanied by a dramatic depletion of pancreatic insulin stores whereas the mIKO:INS4000 diabetic animals could live for several months. This suggests a possible link between the structure of the human INS gene promoter and the type of diabetes developed in these lines.

Preventing polyglutamine-induced activation of c-Jun delays neuronal dysfunction in a mouse model of SCA7 retinopathy.

We have approached the role of cellular stress in neurodegenerative diseases caused by polyglutamine expansion (polyQ) in the context of Spinocerebellar ataxia type 7 (SCA7) that includes retinal degeneration. Using the R7E mouse, in which polyQ-ataxin-7 is specifically over-expressed in rod photoreceptors, we previously showed that rod dysfunction correlated to moderate and prolonged activation of the JNK/c-Jun stress pathway. SCA7 retinopathy was also associated with reduced expression of rod-specific genes, including the transcription factor Nrl, which is essential for rod differentiation and function. Here, we report that R7E retinopathy is improved upon breeding with the JunAA knock-in mice, in which JNK-mediated activation of c-Jun is compromised. Expression of Nrl and its downstream targets, which are involved in phototranduction, are partially restored in the JunAA-R7E mice. We further show that c-Jun can directly repress the transcription of Nrl. Our studies suggest that polyQ-induced cellular stress leads to repression of genes necessary for neuronal fate and function.

Glutamine-expanded ataxin-7 alters TFTC/STAGA recruitment and chromatin structure leading to photoreceptor dysfunction.

Spinocerebellar ataxia type 7 (SCA7) is one of several inherited neurodegenerative disorders caused by a polyglutamine (polyQ) expansion, but it is the only one in which the retina is affected. Increasing evidence suggests that transcriptional alterations contribute to polyQ pathogenesis, although the mechanism is unclear. We previously demonstrated that the SCA7 gene product, ataxin-7 (ATXN7), is a subunit of the GCN5 histone acetyltransferase-containing coactivator complexes TFTC/STAGA. We show here that TFTC/STAGA complexes purified from SCA7 mice have normal TRRAP, GCN5, TAF12, and SPT3 levels and that their histone or nucleosomal acetylation activities are unaffected. However, rod photoreceptors from SCA7 mouse models showed severe chromatin decondensation. In agreement, polyQ-expanded ataxin-7 induced histone H3 hyperacetylation, resulting from an increased recruitment of TFTC/STAGA to specific promoters. Surprisingly, hyperacetylated genes were transcriptionally down-regulated, and expression analysis revealed that nearly all rod-specific genes were affected, leading to visual impairment in SCA7 mice. In conclusion, we describe here a set of events accounting for SCA7 pathogenesis in the retina, in which polyQ-expanded ATXN7 deregulated TFTC/STAGA recruitment to a subset of genes specifically expressed in rod photoreceptors, leading to chromatin alterations and consequent progressive loss of rod photoreceptor function.

Polyglutamine expansion causes neurodegeneration by altering the neuronal differentiation program.

Huntington's disease (HD) and spinocerebellar ataxia type 7 (SCA7) belong to a group of inherited neurodegenerative diseases caused by polyglutamine (polyQ) expansion in corresponding proteins. Transcriptional alteration is a unifying feature of polyQ disorders; however, the relationship between polyQ-induced gene expression deregulation and degenerative processes remains unclear. R6/2 and R7E mouse models of HD and SCA7, respectively, present a comparable retinal degeneration characterized by progressive reduction of electroretinograph activity and important morphological changes of rod photoreceptors. The retina, which is a simple central nervous system tissue, allows correlating functional, morphological and molecular defects. Taking advantage of comparing polyQ-induced degeneration in two retina models, we combined gene expression profiling and molecular biology techniques to decipher the molecular pathways underlying polyQ expansion toxicity. We show that R7E and R6/2 retinal phenotype strongly correlates with loss of expression of a large cohort of genes specifically involved in phototransduction function and morphogenesis of differentiated rod photoreceptors. Accordingly, three key transcription factors (Nrl, Crx and Nr2e3) controlling rod differentiation genes, hence expression of photoreceptor specific traits, are down-regulated. Interestingly, other transcription factors known to cause inhibitory effects on photoreceptor differentiation when mis-expressed, such as Stat3, are aberrantly re-activated. Thus, our results suggest that independently from the protein context, polyQ expansion overrides the control of neuronal differentiation and maintenance, thereby causing dysfunction and degeneration.

Disease progression despite early loss of polyglutamine protein expression in SCA7 mouse model.

Nine neurodegenerative diseases including Huntington's disease (HD) and spinocerebellar ataxia type 7 (SCA7) are caused by an expansion of a polyglutamine (polyQ) stretch in the respective proteins. Aggregation of expanded polyQ-containing proteins into the nucleus is a hallmark of these diseases. Recent evidence indicates that transcriptional dysregulation may contribute to the molecular pathogenesis of these diseases. Using SCA7 and HD mouse models in which we recently described a retinal phenotype, we investigated whether altered gene expression underlies photoreceptor dysfunction. In both models, rhodopsin promoter activity was early and dramatically repressed, suggesting that downregulation of photoreceptor-specific genes plays a major role in polyQ-induced retinal dysfunction. Because the rhodopsin promoter drives mutant ataxin-7 expression in our SCA7 mice, we also assessed whether downregulation of mutant SCA7 transgene would reverse retinopathy progression and aggregate formation. Although residual expression of mutant ataxin-7 was found negligible from 9 weeks of age, SCA7 transgenic mice showed a progressive decline of photoreceptor activity leading to a complete loss of electroretinographic responses from 1 year of age. At this age, aggregates were cleared in only half of the photoreceptors, indicating that their formation is not fully reversible in this model. We demonstrate here that abolishing full-length mutant ataxin-7 expression did not reverse retinopathy progression in SCA7 mice, raising the possibility that some polyQ-induced pathological events might be irreversible.