Genetic myostatin decrease in the golden retriever muscular dystrophy model does not significantly affect the ubiquitin proteasome system despite enhancing the severity of disease

Recent studies suggest that inhibiting the protein myostatin, a negative regulator of skeletal muscle mass, may improve outcomes in patients with Duchenne muscular dystrophy by enhancing muscle mass. When the dystrophin-deficient golden retriever muscular dystrophy (GRMD) dog was bred with whippets having a heterozygous mutation for the myostatin gene, affected GRMD dogs with decreased myostatin (GRippets) demonstrated an accelerated physical decline compared to related affected GRMD dogs with full myostatin. To examine the role of the ubiquitin proteasome and calpain systems in this accelerated decline, we determined the expression of the muscle ubiquitin ligases MuRF1, Atrogin-1, RNF25, RNF11, and CHIP: the proteasome subunits PSMA6, PSMB4, and PSME1: and calpain 1/2 by real time PCR in the cranial sartorius and vastus lateralis muscles in control, affected GRMD, and GRippet dogs. While individual affected GRMD and GRippet dogs contributed to an increased variability seen in ubiquitin ligase expression, neither group was significantly different from the control group. The affected GRMD dogs demonstrated significant increases in caspase-like and trypsin-like activity in the cranial sartorius; however, all three proteasome activities in the GRippet muscles did not differ from controls. Increased variability in calpain 1 and calpain 2 expression and activity in the affected GRMD and GRippet groups were identified, but no statistical differences from the control group were seen. These studies suggest a role of myostatin in the disease progression of GRMD, which does not significantly involve key components of the ubiquitin proteasome and calpain systems involved in the protein quality control of sarcomere and other structural skeletal muscle proteins

Modulation of nucleobindin-1 and nucleobindin-2 by caspases

Nucleobindin-1 and nucleobindin-2 are multifunctional proteins that interact with Ca2+, nucleic acids, and various regulatory proteins in different signaling pathways. So far, our understanding of the regulation of the biological functions of nucleobindins remains limited. In our proteome-wide selection for downstream caspase substrates, both nucleobindin-1 and nucleobindin-2 are found to be the downstream substrates of caspases. We report here the detailed analyses of the cleavage of nucleobindins by caspases. Significantly, the caspase cleavage sites are located exactly at one of the Ca2+-binding EF-hand motifs. Our results suggest that the functions of nucleobindins could be modulated by caspase-mediated cleavage in apoptosis

Dystrophin-deficient dogs with reduced myostatin have unequal muscle growth and greater joint contractures

Abstract Background Myostatin (Mstn) is a negative regulator of muscle growth whose inhibition promotes muscle growth and regeneration. Dystrophin-deficient mdx mice in which myostatin is knocked out or inhibited postnatally have a less severe phenotype with greater total mass and strength and less fibrosis and fatty replacement of muscles than mdx mice with wild-type myostatin expression. Dogs with golden retriever muscular dystrophy (GRMD) have previously been noted to have increased muscle mass and reduced fibrosis after systemic postnatal myostatin inhibition. Based partly on these results, myostatin inhibitors are in development for use in human muscular dystrophies. However, persisting concerns regarding the effects of long-term and profound myostatin inhibition will not be easily or imminently answered in clinical trials. Methods To address these concerns, we developed a canine (GRippet) model by crossbreeding dystrophin-deficient GRMD dogs with Mstn-heterozygous (Mstn +/−) whippets. A total of four GRippets (dystrophic and Mstn +/−), three GRMD (dystrophic and Mstn wild-type) dogs, and three non-dystrophic controls from two litters were evaluated. Results Myostatin messenger ribonucleic acid (mRNA) and protein levels were downregulated in both GRMD and GRippet dogs. GRippets had more severe postural changes and larger (more restricted) maximal joint flexion angles, apparently due to further exaggeration of disproportionate effects on muscle size. Flexors such as the cranial sartorius were more hypertrophied on magnetic resonance imaging (MRI) in the GRippets, while extensors, including the quadriceps femoris, underwent greater atrophy. Myostatin protein levels negatively correlated with relative cranial sartorius muscle cross-sectional area on MRI, supporting a role in disproportionate muscle size. Activin receptor type IIB (ActRIIB) expression was higher in dystrophic versus control dogs, consistent with physiologic feedback between myostatin and ActRIIB. However, there was no differential expression between GRMD and GRippet dogs. Satellite cell exhaustion was not observed in GRippets up to 3 years of age. Conclusions Partial myostatin loss may exaggerate selective muscle hypertrophy or atrophy/hypoplasia in GRMD dogs and worsen contractures. While muscle imbalance is not a feature of myostatin inhibition in mdx mice, findings in a larger animal model could translate to human experience with myostatin inhibitors

A year of genomic surveillance reveals how the SARS-CoV-2 pandemic unfolded in Africa.

The progression of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in Africa has so far been heterogeneous, and the full impact is not yet well understood. In this study, we describe the genomic epidemiology using a dataset of 8746 genomes from 33 African countries and two overseas territories. We show that the epidemics in most countries were initiated by importations predominantly from Europe, which diminished after the early introduction of international travel restrictions. As the pandemic progressed, ongoing transmission in many countries and increasing mobility led to the emergence and spread within the continent of many variants of concern and interest, such as B.1.351, B.1.525, A.23.1, and C.1.1. Although distorted by low sampling numbers and blind spots, the findings highlight that Africa must not be left behind in the global pandemic response, otherwise it could become a source for new variants

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance.

Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern-particularly Alpha, Beta, Delta, and Omicron-on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Unexpected interference of baby wash products with a cannabinoid (THC) immunoassay

Objectives: The results of newborn drug screening have far-reaching impact not only in healthcare, but also in the legal domain. Therefore, the accuracy of these results cannot be undervalued. When false positive cannabinoid (THC) screening results for this population were suspected at our institution, a multidisciplinary approach was initiated to evaluate the screening process for any pre-analytical or analytical sources of error or interference. Design and methods: Mixtures of drug-free urine with various commercial products and materials that commonly contact newborns in our nursery were prepared and tested using the immunoassay screening methods in our laboratory. Additional commercial products were similarly tested; and when available, individual surfactants common to the interfering products were also evaluated. Results: Addition of Head-to-Toe Baby Wash to drug-free urine produced a dose dependent measureable response in the THC immunoassay. Addition of other commercially available baby soaps gave similar results, and subsequent testing identified specific chemical surfactants that reacted with the THC immunoassay. Conclusion: We have identified commonly used soap and wash products used for newborn and infant care as potential causes of false positive THC screening results. Such results in this population can lead to involvement by social services or false child abuse allegations. Given these consequences, it is important for laboratories and providers to be aware of this potential source for false positive screening results and to consider confirmation before initiating interventions. Most importantly, we demonstrate the need for active involvement in the "total testing process," as sources of error are not confined to the laboratory walls

Lacosamide Isothiocyanate-Based Agents: Novel Agents To Target and Identify Lacosamide Receptors

(R)-Lacosamide ((R)-2, (R)-N-benzyl 2-acetamido-3-methoxypropionamide), has recently gained regulatory approval for the treatment of partial-onset seizures in adults. Whole animal pharmacological studies have documented that (R)-2 function is unique. A robust strategy is advanced for the discovery of interacting proteins associated with function and toxicity of (R)-2 through the use of (R)-2 analogs, 3, that contain “affinity bait (AB)” and “chemical reporter (CR)” functional groups. In 3, covalent modification of the interacting proteins proceeds at the AB moiety, and detection or isolation of the selectively captured protein occurs through the bioorthogonal CR group upon reaction with an appropriate probe. We report the synthesis, pharmacological evaluation, and interrogation of the mouse soluble brain proteome using 3 where the AB group is an isothiocyanate moiety. One compound, (R)-N-(4-isothiocyanato)benzyl 2-acetamido-3-(prop-2-ynyloxy)propionamide ((R)-9), exhibited excellent seizure protection in mice and, like (R)-2, anticonvulsant activity principally resided in the (R)-stereoisomer. Several proteins were preferentially labeled by (R)-9 compared with (S)-9, including collapsin response mediator protein 2