New Horizons in Myotonic Dystrophy Type 1: Cellular Senescence as a Therapeutic Target.

Myotonic dystrophy type 1 (DM1) is considered a progeroid disease (i.e., causing premature aging).

Dysregulation of alternative splicing is a transcriptomic feature of patient-derived fibroblasts from CAG repeat expansion spinocerebellar ataxias.

The spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of rare dominantly inherited neurodegenerative diseases characterized by progressive ataxia. The most common mutation seen across the SCAs is a CAG repeat expansion, causative for SCA1, 2, 3, 6, 7, 12 and 17. We recently identified dysregulation of alternative splicing as a novel, presymptomatic transcriptomic hallmark in mouse models of SCAs 1, 3 and 7.

Alternative splicing dysregulation across tissue and therapeutic approaches in a mouse model of myotonic dystrophy type 1.

Myotonic dystrophy type 1 (DM1), the leading cause of adult-onset muscular dystrophy, is caused by a CTG repeat expansion. Expression of the repeat causes widespread alternative splicing (AS) defects and downstream pathogenesis, including significant skeletal muscle impacts. The mouse model plays a significant role in therapeutic development.

CAG repeat-selective compounds reduce abundance of expanded CAG RNAs in patient cell and murine models of SCAs.

Spinocerebellar ataxias (SCAs) are a genetically heterogenous group of devastating neurodegenerative conditions for which clinical care currently focuses on managing symptoms. Across these diseases there is an unmet need for therapies that address underlying disease mechanisms. We utilised the shared CAG repeat expansion mutation causative for a large subgroup of SCAs, to develop a novel disease-gene independent and mechanism agnostic small molecule screening approach to identify compounds with therapeutic potential across multiple SCAs.

Expression levels of core spliceosomal proteins modulate the MBNL-mediated spliceopathy in DM1.

Myotonic dystrophy type 1 (DM1) is a heterogeneous multisystemic disease caused by a CTG repeat expansion in DMPK. Transcription of the expanded allele produces toxic CUG repeat RNA that sequesters the MBNL family of alternative splicing (AS) regulators into ribonuclear foci, leading to pathogenic mis-splicing. To identify genetic modifiers of toxic CUG RNA levels and the spliceopathy, we performed a genome-scale siRNA screen using an established HeLa DM1 repeat-selective screening platform.

Zika virus infection in a cell culture model reflects the transcriptomic signatures in patients.

Zika virus (ZIKV), a re-emerging flavivirus, is associated with devasting developmental and neurological disease outcomes particularly in infants infected . Towards understanding the molecular underpinnings of the unique ZIKV disease pathologies, numerous transcriptome-wide studies have been undertaken. Notably, these studies have overlooked the assimilation of RNA-seq analysis from ZIKV-infected patients with cell culture model systems.

Mutation of two intronic nucleotides alters RNA structure and dynamics inhibiting MBNL1 and RBFOX1 regulated splicing of the Insulin Receptor.

Alternative splicing (AS) of Exon 11 of the Insulin Receptor ( ) is highly regulated and disrupted in several human disorders. To better understand exon 11 AS regulation, splicing activity of an exon 11 minigene reporter was measured across a gradient of the AS regulator muscleblind-like 1 protein (MBNL1). The RNA-binding protein Fox-1 (RBFOX1) was added to determine its impact on MBNL1-regulated splicing.

Confidence and Utilization are Poorly Associated with Point-of-Care Ultrasound Competency among Internal Medicine Trainees.

Introduction: Point-of-Care Ultrasound (POCUS) is the utilization of bedside ultrasound by clinicians. Its portable and rapid diagnostic capabilities make it an excellent tool for deployment and mobile military settings. However, formal and uniform POCUS training is lacking.

Widespread alternative splicing dysregulation occurs presymptomatically in CAG expansion spinocerebellar ataxias.

The spinocerebellar ataxias (SCAs) are a group of dominantly inherited neurodegenerative diseases, several of which are caused by CAG expansion mutations (SCAs 1, 2, 3, 6, 7 and 12) and more broadly belong to the large family of over 40 microsatellite expansion diseases. While dysregulation of alternative splicing is a well defined driver of disease pathogenesis across several microsatellite diseases, the contribution of alternative splicing in CAG expansion SCAs is poorly understood. Furthermore, despite extensive studies on differential gene expression, there remains a gap in our understanding of presymptomatic transcriptomic drivers of disease.

Implementation and Evaluation of a Longitudinal Flipped-Classroom Point-of-Care Ultrasound Curriculum at an Internal Medicine Residency Program.

Background: Point-of-care ultrasound (POCUS) has extensive clinical utility in internal medicine, but formal and uniform curricula in internal medicine are lacking.

Objective: To determine the effectiveness of a longitudinal, flipped-classroom, academic half-day curriculum on internal medicine resident confidence, utilization, and changes in clinical management.

Methods: We implemented an asynchronous, flipped-classroom, academic half-day curriculum from November 2020 to November 2021 and conducted an evaluation with a prospective, before-after cohort study.

Individual transcriptomic response to strength training for patients with myotonic dystrophy type 1.

Myotonic dystrophy type 1 (DM1), the most common form of adult-onset muscular dystrophy, is caused by a CTG expansion resulting in significant transcriptomic dysregulation that leads to muscle weakness and wasting. While strength training is clinically beneficial in DM1, molecular effects had not been studied. To determine whether training rescued transcriptomic defects, RNA-Seq was performed on vastus lateralis samples from 9 male patients with DM1 before and after a 12-week strength-training program and 6 male controls who did not undergo training.

Alternative Splicing Outcomes Across an RNA-Binding Protein Concentration Gradient.

Alternative splicing (AS) is a dynamic RNA processing step that produces multiple RNA isoforms from a single pre-mRNA transcript and contributes to the complexity of the cellular transcriptome and proteome. This process is regulated through a network of cis-regulatory sequence elements and trans-acting factors, most-notably RNA binding proteins (RBPs). The muscleblind-like (MBNL) and RNA binding fox-1 homolog (RBFOX) are two well characterized families of RBPs that regulate fetal to adult AS transitions critical for proper muscle, heart, and central nervous system development.

Quercetin selectively reduces expanded repeat RNA levels in models of myotonic dystrophy.

Myotonic dystrophy is a multisystemic neuromuscular disease caused by either a CTG repeat expansion in (DM1) or a CCTG repeat expansion in (DM2). Transcription of the expanded alleles produces toxic gain-of-function RNA that sequester the MBNL family of alternative splicing regulators into ribonuclear foci, leading to pathogenic mis-splicing. There are currently no approved treatments that target the root cause of disease which is the production of the toxic expansion RNA molecules.

Disease-associated inosine misincorporation into RNA hinders translation.

Failure to prevent accumulation of the non-canonical nucleotide inosine triphosphate (ITP) by inosine triphosphate pyrophosphatase (ITPase) during nucleotide synthesis results in misincorporation of inosine into RNA and can cause severe and fatal developmental anomalies in humans. While the biochemical activity of ITPase is well understood, the pathogenic basis of ITPase deficiency and the molecular and cellular consequences of ITP misincorporation into RNA remain cryptic. Here, we demonstrate that excess ITP in the nucleotide pool during in vitro transcription results in T7 polymerase-mediated inosine misincorporation in luciferase RNA.

Whistling Scrotum: An Unusual Presentation of Pneumomediastinum in the Setting of an Open Scrotal Wound.

BACKGROUND Pneumoscrotum is a rare clinical occurrence in which air accumulates in the scrotum. The origin of air is primarily from trauma, but spontaneous pneumoscrotum can develop from gastrointestinal or pulmonary sources. Physical examination of pneumoscrotum typically includes crepitus of the perineal region and scrotal swelling and associated findings depending on the origin of the free air.

Addressing Persistent Vaccine Hesitancy in a Military Community Through a Physician-Led Intervention.

Introduction: Following the identification of coronavirus disease 2019 (COVID-19) in China, the virus has spread rapidly around the world causing severe illness and death. Several vaccines were found to be safe and effective and made available first to those most at risk and then to the general public. Despite the safety and efficacy profiles, vaccine hesitancy remains a significant barrier to widespread immunity.

Molecular characterization of myotonic dystrophy fibroblast cell lines for use in small molecule screening.

Myotonic dystrophy type 1 (DM1) and type 2 (DM2) are common forms of adult onset muscular dystrophy. Pathogenesis in both diseases is largely driven by production of toxic-expanded repeat RNAs that sequester MBNL RNA-binding proteins, causing mis-splicing. Given this shared pathogenesis, we hypothesized that diamidines, small molecules that rescue mis-splicing in DM1 models, could also rescue mis-splicing in DM2 models.

CCG•CGG interruptions in high-penetrance SCA8 families increase RAN translation and protein toxicity.

Spinocerebellar ataxia type 8 (SCA8), a dominantly inherited neurodegenerative disorder caused by a CTG•CAG expansion, is unusual because most individuals that carry the mutation do not develop ataxia. To understand the variable penetrance of SCA8, we studied the molecular differences between highly penetrant families and more common sporadic cases (82%) using a large cohort of SCA8 families (n = 77). We show that repeat expansion mutations from individuals with multiple affected family members have CCG•CGG interruptions at a higher frequency than sporadic SCA8 cases and that the number of CCG•CGG interruptions correlates with age at onset.

Impact of an Education Intervention on COVID-19 Vaccine Hesitancy in a Military Base Population.

Background: Coronavirus disease 2019 (COVID-19) vaccine hesitancy is a major impediment to achieving herd immunity and overcoming the current pandemic. Our aim was to decrease the prevalence of vaccine hesitancy through an education intervention.

Method: An education intervention, consisting of a PowerPoint presentation addressing the two mRNA COVID-19 vaccine concerns/myths and a question and answer panel comprising health care providers from various specialties, was implemented to address vaccine hesitancy among personnel associated with Wright-Patterson Air Force Base through a series of virtual and in-person seminars.

Longitudinal Changes in Spirometry in Deployed Air Force Firefighters.

Introduction: Inhalational exposures are common among service members who deploy to southwest Asia. The objective of this study is to determine if deployed Air Force firefighters have any decline in spirometry related to deployment.

Methods: This study is a retrospective chart review.

Autologous Stem Cell Transplantation in the Treatment of Pulmonary Light Chain Deposition Disease.

Light chain deposition disease is a rare condition that results in the deposition of light chains in organs and their subsequent dysfunction. It is often the consequence of unchecked light chain production by a plasma cell clone. Rarely does it manifest with solely pulmonary involvement, especially in the young otherwise healthy patient.

Zebrafish mbnl mutants model physical and molecular phenotypes of myotonic dystrophy.

The muscleblind RNA-binding proteins (MBNL1, MBNL2 and MBNL3) are highly conserved across vertebrates and are important regulators of RNA alternative splicing. Loss of MBNL protein function through sequestration by CUG or CCUG RNA repeats is largely responsible for the phenotypes of the human genetic disorder myotonic dystrophy (DM). We generated the first stable zebrafish (Danio rerio) models of DM-associated MBNL loss of function through mutation of the three zebrafish mbnl genes.

Perceptions and Concerns Regarding COVID-19 Vaccination in a Military Base Population.

Introduction: Safe and effective vaccines against severe acute respiratory syndrome-associated coronavirus 2 are essential tools in the fight against the coronavirus disease 2019  (COVID-19) pandemic. However, hesitancy to vaccination is a major barrier to achieving herd immunity, particularly among a population working on a military base. To better understand the perceptions and concerns of these individuals, a voluntary survey was conducted.

Repeat length increases disease penetrance and severity in C9orf72 ALS/FTD BAC transgenic mice.

C9orf72 ALS/FTD patients show remarkable clinical heterogeneity, but the complex biology of the repeat expansion mutation has limited our understanding of the disease. BAC transgenic mice were used to better understand the molecular mechanisms and repeat length effects of C9orf72 ALS/FTD. Genetic analyses of these mice demonstrate that the BAC transgene and not integration site effects cause ALS/FTD phenotypes.