Eric Olson

Cancer cachexia is a prevalent and often fatal wasting condition that cannot be fully reversed with nutritional interventions. Muscle atrophy is a central component of the syndrome, but the mechanisms whereby cancer leads to skeletal muscle atrophy are not well understood. We performed single-nucleus multi-omics on skeletal muscles from a mouse mod...

Rhabdomyosarcoma (RMS) is the most common type of soft tissue sarcoma in children and adolescents. Fusion-Negative RMS (FN-RMS) accounts for more than 80% of all RMS cases. The long-term event-free survival rate for patients with high grade FN-RMS is below 30%, highlighting the need for improved therapeutic strategies. CD73 is a 5’ ectonucleotidase...

During development, cells make switch-like decisions to activate new gene programs specifying cell lineage. The mechanisms underlying these decisive choices remain unclear. Here, we show that the cardiovascular transcriptional coactivator myocardin (MYOCD) activates cell identity genes by concentration-dependent and switch-like formation of transcr...

Rhabdomyosarcoma (RMS) is the most common type of soft tissue sarcoma in children and adolescents. Fusion-negative RMS (FN-RMS) accounts for more than 80% of all RMS cases. The long-term event-free survival rate for patients with high-grade FN-RMS is below 30%, highlighting the need for improved therapeutic strategies. CD73 is a 5′ ectonucleotidase...

BACKGROUND The p.Arg14del variant of the PLN (phospholamban) gene causes cardiomyopathy, leading to severe heart failure. Calcium handling defects and perinuclear PLN aggregation have both been suggested as pathological drivers of this disease. Dwarf open reading frame (DWORF) has been shown to counteract PLN regulatory calcium handling function in...

During cardiovascular development, cells make switch-like decisions to activate the expression of new gene programs leading to lineage specification. The mechanisms underlying these decisive choices remain unclear. Myocardin is a cardiomyocyte and smooth muscle cell specific transcriptional coactivator, which is necessary and important for activati...

Direct reprogramming of resident cardiac fibroblasts into cardiomyocytes is an attractive strategy to restore cardiac function following myocardial infarction (MI). However, canonical and extensively studied reprogramming factors (e.g. Gata4, Mef2c, Tbx5) have shown to be ineffective in reprogramming adult human fibroblasts. Furthermore, current hu...

Aims RNA binding proteins play essential roles in mediating RNA splicing and are key post-transcriptional regulators in the heart. Our recent study demonstrated that RBPMS (RNA binding protein with multiple splicing) is crucial for cardiac development through modulating mRNA splicing, but little is known about its functions in the adult heart. In t...

Cardiovascular diseases are the most common cause of worldwide morbidity and mortality, highlighting the necessity for advanced therapeutic strategies. Ca2+/calmodulin-dependent protein kinase IIδ (CaMKIIδ) is a prominent inducer of various cardiac disorders, which is mediated by two oxidation-sensitive methionine residues within the regulatory dom...

The fusion of mononucleated myoblasts produces multinucleated muscle fibers leading to the formation of skeletal muscle. Myomaker, a skeletal muscle-specific membrane protein, is essential for myoblast fusion. Here we report the cryo-EM structures of mouse Myomaker (mMymk) and Ciona robusta Myomaker (cMymk). Myomaker contains seven transmembrane he...

BACKGROUND Cardiovascular diseases are the main cause of worldwide morbidity and mortality, highlighting the need for new therapeutic strategies. Autophosphorylation and subsequent overactivation of the cardiac stress-responsive enzyme CaMKIIδ (Ca ²⁺ /calmodulin-dependent protein kinase IIδ) serves as a central driver of multiple cardiac disorders....

Direct cardiac reprogramming of fibroblasts to cardiomyocytes presents an attractive therapeutic strategy to restore cardiac function following injury. Cardiac reprogramming was initially achieved through the overexpression of the transcription factors Gata4, Mef2c, and Tbx5 (GMT), and later, Hand2 (GHMT) and Akt1 (AGHMT) were found to further enha...

We previously identified a neonatal cardiomyocyte population that enters the cell-cycle following injury and disappears as the heart loses the ability to regenerate. These regenerative neonatal cardiomyocytes display a unique transcriptional program regulated by NFYA, a subunit of the trimeric complex Nuclear Transcription Factor Y (NFY) that funct...

During heart development, cardiomyocytes display reduced proliferation and enhanced contractility to support cardiac functional maturation, but the mechanistic basis is not fully understood. Alternative RNA splicing is an important mechanism of RNA posttranscriptional modification and gene regulation in the heart. In studying a cardiac RNA binding...

The neonatal mouse heart regenerates after injury without scarring or impairment in heart function, but this ability is lost within the first week of life. This regenerative time window coincides with important changes in immune cell composition, maturation, and function. To understand how these changes support regeneration over scarring in the neo...

Skeletal muscle fibers express distinct gene programs during development and maturation, but the underlying gene regulatory networks that confer stage-specific myofiber properties remain unknown. To decipher these distinctive gene programs and how they respond to neural activity, we generated a combined multi-omic single-nucleus RNA-seq and ATAC-se...

Mutations in genes encoding nuclear envelope proteins lead to diseases known as nuclear envelopathies, characterized by skeletal muscle and heart abnormalities, such as Emery-Dreifuss muscular dystrophy (EDMD). The tissue-specific role of the nuclear envelope in the etiology of these diseases has not been extensively explored. We previously showed...

Rhabdomyosarcoma (RMS) is a common soft tissue sarcoma in children that resembles developing skeletal muscle. Unlike normal muscle cells, RMS cells fail to differentiate despite expression of the myogenic determination protein MYOD. The TWIST2 transcription factor is frequently overexpressed in fusion-negative RMS (FN-RMS). TWIST2 blocks differenti...

Duchenne muscular dystrophy (DMD) is a debilitating genetic disorder that results in progressive muscle degeneration and weakness. DMD is caused by mutations in the gene encoding dystrophin protein, a membrane-associated protein required for maintenance of muscle structure and function. Although the genetic mutations causing the disease are well kn...

Duchenne muscular dystrophy (DMD) is a fatal X-linked recessive disease of progressive muscle weakness and wasting caused by the absence of dystrophin protein. Current gene therapy approaches using antisense oligonucleotides require lifelong dosing and have limited efficacy in restoring dystrophin production. A gene editing approach could permanent...

Direct reprogramming of resident cardiac fibroblasts to induced cardiomyocytes is an attractive therapeutic strategy to restore function and remuscularize the injured heart. The cardiac transcription factors Gata4, Mef2c, and Tbx5 have been the mainstay of direct cardiac reprogramming strategies for the past decade. Yet, recent discoveries have ide...

The most common form of genetic heart disease is hypertrophic cardiomyopathy (HCM), which is caused by variants in cardiac sarcomeric genes and leads to abnormal heart muscle thickening. Complications of HCM include heart failure, arrhythmia and sudden cardiac death. The dominant-negative c.1208G>A (p.R403Q) pathogenic variant (PV) in β-myosin (MYH...

Our dream of defeating the processes of organ damage and aging remains a challenge scientists pursued for hundreds of years. Although the goal is to successfully treat the body as a whole, steps towards regenerating individual organs are even considered significant. Since initial approaches utilizing only progenitor cells appear limited, we propose...

CRISPR-Cas9 gene editing is emerging as a prospective therapy for genomic mutations. However, current editing approaches are directed primarily toward relatively small cohorts of patients with specific mutations. Here, we describe a cardioprotective strategy potentially applicable to a broad range of patients with heart disease. We used base editin...

Mutations in RNA binding motif protein 20 ( RBM20 ) are a common cause of familial dilated cardiomyopathy (DCM). Many RBM20 mutations cluster within an arginine/serine-rich (RS-rich) domain, which mediates nuclear localization. These mutations induce RBM20 mis-localization to form aberrant ribonucleoprotein (RNP) granules in the cytoplasm of cardio...

Duchenne muscular dystrophy (DMD) is a fatal neuromuscular disorder, caused by mutations in the DMD gene coding dystrophin. Applying clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (CRISPR-Cas) for therapeutic gene editing represents a promising technology to correct this devastating disease through...

Mutations in nuclear envelope proteins (NEPs) cause devastating genetic diseases, known as envelopathies, that primarily affect the heart and skeletal muscle. A mutation in the NEP LEM domain-containing protein 2 (LEMD2) causes severe cardiomyopathy in humans. However, the roles of LEMD2 in the heart and the pathological mechanisms responsible for...

Introduction: Despite current medical advancements, effective treatment for familial cardiomyopathies remains challenging. Mutations in RNA binding motif protein 20 ( RBM20 ) are a common cause of dilated cardiomyopathy (DCM). Many RBM20 mutations cluster within the arginine/serine rich (RS-rich) domain, which mediates nuclear localization. These m...

Background: Human pluripotent stem cell-derived muscle models show great potential for translational research. Here, we describe developmentally inspired methods for the derivation of skeletal muscle cells and their utility in skeletal muscle tissue engineering with the aim to model skeletal muscle regeneration and dystrophy in vitro. Methods: K...

Background & Objectives: SR Ca2+ load, which is sustained by SERCA2a pump activity, is a critical determinant for cardiac performance regulation & adaptation. Independent studies identified both S100A1 & STRIT1 as molecular enhancers of SERCA2a activity in the heart. S100A1 & STRIT1 decline in post-myocardial infarction hearts aggravated the transi...

Noncompaction cardiomyopathy is a common congenital cardiac disorder associated with abnormal ventricular cardiomyocyte trabeculation and impaired pump function. The genetic basis and underlying mechanisms of this disorder remain elusive. We show that genetic deletion of RNA binding protein with multiple splicing (Rbpms), an uncharacterized RNA bin...

The Nuclear Transcription Factor Y (NF-Y) is a trimeric complex composed of subunits NF-Ya, NF-Yb, and NF-Yc. While all three subunits are expressed across tissues and cell types, the activity of the NF-Y complex is largely dependent on the expression of its DNA-binding subunit NF-Ya. NF-Y functions as a pioneer factor in regulating gene transcript...

Mutations in nuclear envelope proteins (NEPs) cause devastating genetic diseases, known as envelopathies, which primarily affect the heart and skeletal muscle. A mutation in the NEP LEMD2 causes severe cardiomyopathy in humans. However, the roles of LEMD2 in the heart and the pathological mechanisms responsible for its association with cardiac dise...

Duchenne muscular dystrophy (DMD) is a lethal neuromuscular disease caused by mutations in the X-linked dystrophin (DMD) gene. Exon deletions flanking exon 51, which disrupt the dystrophin open reading frame (ORF), represent one of the most common types of human DMD mutations. Previously, we used CRISPR-Cas9 gene editing to restore the reading fram...

Rhabdomyosarcoma (RMS) is an aggressive pediatric soft tissue sarcoma of myoblast origin. RMS tumors are unable to terminally differentiate into syncytial muscle despite elevated expression of the muscle master regulators, MyoD and Myf5. Fusion-positive RMS (FP-RMS) and fusion-negative RMS (FN-RMS) have emerged as the two major RMS subtypes. The pa...

Cardiovascular disease remains the leading cause of morbidity and mortality in the developed world. In recent decades, extraordinary effort has been devoted to defining the molecular and pathophysiological characteristics of the diseased heart and vasculature. Mouse models have been especially powerful in illuminating the complex signaling pathways...

Skeletal muscle fibers contain hundreds of nuclei, which increase the overall transcriptional activity of the tissue and perform specialized functions. Multinucleation occurs through myoblast fusion, mediated by the muscle fusogens Myomaker (MYMK) and Myomixer (MYMX). We describe a human pedigree harboring a recessive truncating variant of the MYMX...

Noncompaction cardiomyopathy is a common congenital cardiac disorder associated with abnormal ventricular cardiomyocyte trabeculation and impaired pump function. The genetic basis and underlying mechanisms of this disorder remain elusive. We show that the genetic deletion of RNA-binding protein with multiple splicing (Rbpms), an uncharacterized RNA...

Duchenne Muscular Dystrophy (DMD) is a lethal muscle disease caused by mutations in the dystrophin gene. CRISPR/Cas9 genome editing has been used to correct DMD mutations in animal models at young ages. However, the longevity and durability of CRISPR/Cas9 editing remained to be determined. To address these issues, we subjected ΔEx44 DMD mice to sys...

Significance Microproteins are a growing class of versatile small proteins previously overlooked by standard gene annotation methods due to their small size. Here we characterize mitolamban as a cardiac-enriched inner mitochondrial membrane–localized microprotein, which interacts with complex III of the electron transport chain and contributes to c...

Cardiomyocyte loss is the underlying basis for a majority of heart diseases. Preventing cardiomyocytes from death (cardioprotection) and replenishing the lost myocardium (regeneration) are the central goals for heart repair. Although cardioprotection and heart regeneration have been traditionally thought to involve separate mechanisms, protection o...

Ischemic heart disease is the leading cause of death worldwide. Direct reprogramming of resident cardiac fibroblasts (CFs) to induced cardiomyocytes (iCLMs) has emerged as a potential therapeutic approach to treat heart failure and ischemic disease. Cardiac reprogramming was first achieved through forced expression of the transcription factors Gata...

Muscular dystrophies are a heterogeneous group of monogenic neuromuscular disorders which lead to progressive muscle loss and degeneration of the musculoskeletal system. The genetic causes of muscular dystrophies are well characterized, but no effective treatments have been developed so far. The discovery and application of the CRISPR/Cas system fo...

Rationale: Absence of dystrophin in Duchenne muscular dystrophy (DMD) results in the degeneration of skeletal and cardiac muscles. Owing to advances in respiratory management of DMD patients, cardiomyopathy has become a significant aspect of the disease. While CRISPR/Cas9 genome editing technology holds great potential as a novel therapeutic avenue...

Significance Duchenne muscular dystrophy (DMD) is a devastating disease caused by mutation in the X-linked dystrophin gene, resulting in skeletal muscle loss and patient premature death. Here, we present an improved protocol for the differentiation of human pluripotent stem cells to the skeletal muscle lineage. Using this protocol for the different...

Ischemic heart disease is the leading cause of morbidity, mortality, and healthcare expenditure worldwide due to an inability of the heart to regenerate following injury. Thus, novel heart failure therapies aimed at promoting cardiomyocyte regeneration are desperately needed. In recent years, direct reprogramming of resident cardiac fibroblasts to...

Significance Activation of brown adipose tissue offers a strategy for enhancing energy expenditure to counteract obesity and other metabolic disorders. The discovery of novel factors regulating brown adipose tissue function has implications in therapeutic intervention to treat metabolic dysfunction. Here, we discover a previously uncharacterized RN...

Duchenne muscular dystrophy (DMD), caused by mutations in the X-linked dystrophin gene, is a lethal neuromuscular disease. Correction of DMD mutations in animal models has been achieved by CRISPR/Cas9 genome editing using Streptococcus pyogenes Cas9 (SpCas9) delivered by adeno-associated virus (AAV). However, due to the limited viral packaging capa...

Myocardin, a potent coactivator of serum response factor (SRF), competes with ternary complex factor (TCF) proteins for SRF binding to balance opposing mitogenic and myogenic gene programs in cardiac and smooth muscle. Here we identify a cardiac lncRNA transcribed adjacent to myocardin, named CARDINAL, which antagonizes SRF-dependent mitogenic gene...

Direct cardiac reprogramming of fibroblasts to cardiomyocytes presents an attractive therapeutic strategy to restore cardiac function following injury. Cardiac reprogramming was initially achieved through overexpression of the transcription factors Gata4, Mef2c and Tbx5; later, Hand2 and Akt1 were found to further enhance this process1–5. Yet, stau...

Lamins and transmembrane proteins within the nuclear envelope regulate nuclear structure and chromatin organization. Nuclear envelope transmembrane protein 39 (Net39) is a muscle nuclear envelope protein whose functions in vivo have not been explored. We show that mice lacking Net39 succumb to severe myopathy and juvenile lethality, with concomitan...

Adverse cardiac remodeling after myocardial infarction (MI) causes structural and functional changes in the heart leading to heart failure. The initial post-MI pro-inflammatory response followed by reparative or anti-inflammatory response is essential for minimizing the myocardial damage, healing, and scar formation. Bone marrow–derived macrophages...

The adult mammalian heart has limited capacity for regeneration following injury, whereas the neonatal heart can readily regenerate within a short period after birth. Neonatal heart regeneration is orchestrated by multiple cell types intrinsic to the heart, as well as immune cells that infiltrate the heart after injury. To elucidate the transcripti...

Significance Skeletal muscle is composed of multinucleated myofibers that are essential for movement and metabolism. Duchenne muscular dystrophy (DMD) is a devastating disease that is caused by the lack of the dystrophin protein, which maintains the integrity of muscle membranes. The absence of dystrophin results in myofiber degeneration followed b...

Introduction: Emerging evidence suggests that many RNA molecules currently annotated as noncoding contain short open reading frames that code for functional small proteins called microproteins. Microproteins play critical roles in a diverse range of essential biological processes. To identify novel cardiac-expressed microproteins, we used a compara...

Direct cardiac reprogramming of fibroblasts to cardiomyocytes presents an attractive therapeutic strategy to restore cardiac function following injury. Cardiac reprogramming was initially achieved through the overexpression of the transcription factors Gata4, Mef2c, and Tbx5 (GMT), and later, Hand2 (GHMT) and Akt1 (AGHMT) were found to further enha...

Introduction: Left Ventricular Assist Devices (LVAD) decrease cardiac mechanical work and metabolic demand and may decrease cardiomyocyte oxidative stress, followed by cell cycle re-entry and cell regeneration. We tested whether LVAD long-term support is associated with myocardial regeneration. Methods: Viability fluorodeoxyglucose (18FDG) - positr...

CRISPR-Cas9 has emerged as a powerful technology that relies on Cas9/sgRNA ribonucleoprotein complexes (RNPs) to target and edit DNA. However, many therapeutic targets cannot currently be accessed due to the lack of carriers that can deliver RNPs systemically. Here, we report a generalizable methodology that allows engineering of modified lipid nan...

Muscular dystrophies are debilitating disorders that result in progressive weakness and degeneration of skeletal muscle. Although the genetic mutations and clinical abnormalities of a variety of neuromuscular diseases are well known, no curative therapies have been developed to date. The advent of genome editing technology provides new opportunitie...

Murine cardiomyocytes undergo proliferation, multinucleation, and polyploidization during the first 3 weeks of postnatal life, resulting in a mixture of diploid and tetraploid cardiomyocytes in the heart. Understanding the molecular differences between diploid and tetraploid cardiomyocytes from these processes has been limited due to lack of unique...

Duchenne muscular dystrophy (DMD), one of the most common neuromuscular disorders of children, is caused by the absence of dystrophin protein in striated muscle. Deletions of exons 43, 45 and 52 represent mutational “hot spot” regions in the dystrophin gene. We created three new DMD mouse models harboring deletions of exons 43, 45 or 52 to represen...

The adult mammalian heart is incapable of regeneration following injury. In contrast, the neonatal mouse heart can efficiently regenerate during the first week of life. The molecular mechanisms that mediate the regenerative response and its blockade in later life are not understood. Here, by single-nucleus RNA sequencing, we map the dynamic transcr...

Duchenne muscular dystrophy (DMD) is a lethal neuromuscular disease caused by mutations in the dystrophin gene ( DMD ). Previously, we applied CRISPR-Cas9–mediated “single-cut” genome editing to correct diverse genetic mutations in animal models of DMD. However, high doses of adeno-associated virus (AAV) are required for efficient in vivo genome ed...

Striated muscles are the skeletal and cardiac muscles that have distinct bands when viewed by a microscope. Although skeletal and cardiac muscles appear similar, they originate from different progenitor cells and use different evolutionarily conserved networks of transcription factors and non-coding RNAs to regulate the programs controlling cell di...

Duchenne muscular dystrophy (DMD) is a fatal genetic disorder caused by mutations in the dystrophin gene. To enable the non-invasive analysis of DMD gene correction strategies in vivo, we introduced a luciferase reporter in-frame with the C-terminus of the dystrophin gene in mice. Expression of this reporter mimics endogenous dystrophin expression...

The adult mammalian heart has limited capacity for regeneration following injury, whereas the neonatal heart can readily regenerate within a short period after birth. To uncover the molecular mechanisms underlying neonatal heart regeneration, we compared the transcriptomes and epigenomes of regenerative and nonregenerative mouse hearts over a 7-d t...

The adult mammalian heart has limited capacity for regeneration following injury, whereas the neonatal heart can readily regenerate within a short period after birth. Deciphering the molecular underpinnings of neonatal heart regeneration and the blockade to regeneration in later life may provide novel insights for heart repair. Neonatal heart regen...

Direct cardiac reprogramming of fibroblasts to cardiomyocytes is an attractive therapeutic strategy to restore cardiac function following injury. The cardiac transcription factors Gata4, Mef2c, and Tbx5 are sufficient to directly reprogram fibroblasts to a cardiac fate and their cardiogenic activity is enhanced by the addition of Hand2 and Akt1. Ho...