Hypertrophic cardiomyopathy (HCM) is the leading genetic cause of heart disease. Although research has been focused on HCM for the past several decades, clinical treatments for patients remain limited. The heart comprises several myofilament proteins that work together to facilitate proper contraction and relaxation to pump blood throughout the body. Cardiac myosin binding protein-C (cMyBP-C) is a thick-filament regulatory protein, and mutations in cMyBP-C are frequently linked with clinical cases of HCM. To further understand the role of cMyBP-C and its contribution to cardiac disease, we assessed the progressive development of molecular and morphological biomarkers associated with HCM in a cMyBP-C knockout mouse model. We assessed gene expression associated with hypertrophy, fibrosis, and sarcomeric proteins at 21, 60, and 183 days of age via a custom NanoString nCounter gene panel designed from clinically relevant human cardiac disease panels. Cardiac morphology and tissue remodeling were evaluated using biochemical and histological assays. Our findings unveil significant dysregulation in genes associated with hypertrophy and fibrosis in cMyBP-C deficient mice at 21 days old, which precedes irreversible overt fibrosis in the cardiac tissue. However, changes in sarcomeric gene expression only appeared after hypertrophy and fibrosis were established. The early changes in gene expression underscore the need for better understanding the mechanisms driving HCM development, which may offer potential avenues for therapeutic intervention before pathological remodeling occurs. Pharmaceutical interventions that target cardiac dysfunction may be most effective before cardiac remodeling, highlighting the potential utility for early screening and preventative strategies to manage genetic-based cardiomyopathies.NEW & NOTEWORTHY The effect of cMyBP-C ablation in the cardiac sarcomere induces cell-signaling changes that precede significant overt fibrosis. These data indicate that early clinical screening may allow for treatment before irreversible, pathological remodeling of the heart takes place.

MicroRNAs (miRNAs) are short noncoding RNAs that regulate gene expression in various cell types. Skeletal muscle consists of bundles of muscle fibers, which are classified as either slow-type or fast-type according to their properties. However, the roles of miRNAs in modulating physiological muscle phenotypes remain unclear. Here, we profiled fiber-type-enriched miRNAs to gain insight into differences in gene regulation between the two fiber types. To avoid cross-contamination, we used GFP-Myh7 mice, in which slow-type muscle fibers express green fluorescent protein (GFP), allowing easy discrimination between GFP-positive slow-type fibers and GFP-negative fast-type fibers under fluorescence microscopy. Here, we profiled miRNA expression in two muscle fiber types in GFP-Myh7 mice. Microarray analysis showed that 18 and 12 miRNAs were highly expressed in slow-type and fast-type fibers, respectively, with >2 log2 fold-change (log2FC) relative to their counterparts. These distinct miRNA expressions were largely consistent with polymerase chain reaction (PCR) results. Gene ontology analyses predicted that target genes of these miRNAs were mainly involved in "regulation of transcription" in slow-type muscle fibers, and in "extracellular matrix (ECM)"-related terms in fast-type fibers. Our results suggest that distinct miRNA expression patterns in each fiber type may participate in modulating fiber-type-specific intracellular and extracellular environments.NEW & NOTEWORTHY Skeletal muscle comprises fast and slow fiber types, which reflect physiological and metabolic features. Although identifying fiber types without PCR or antibody-based assays was challenging, we visually isolated slow- and fast-type fibers from GFP-Myh7 mice, in which slow-type fibers express green fluorescent protein (GFP). Using these mice, we successfully profiled miRNA expression in precisely distinguished slow- and fast-type fibers to capture fiber-type-dependent miRNA expression.

Dorsal root ganglia (DRG) are essential for transmitting sensory information from visceral organs to the central nervous system. Sensory neuronal hyperactivity and glial reactivity have been reported in DRG in animal models of chronic pain, yet the molecular mechanisms contributing to the pathogenesis of visceral pain remain unclear. In this study, we performed transcriptome profiling of lumbosacral DRG in a mouse model of chronic pelvic pain, focusing on mapping the gene and signaling pathway changes associated with visceral hypersensitivity in lumbosacral DRG transmitting bladder afferent signals. Using the bulk RNA-sequencing method, we identified differentially expressed genes in the lumbosacral DRG between control mice and mice exhibiting visceral pain symptoms, with striking sex differences in identified genes. Hierarchical gene clustering analysis and Ingenuity Pathways Analysis both revealed sex-specific signaling pathway activation associated with visceral pain conditions, including glial activation and nociceptive sensitization in males and heightened immune activation in females. Interestingly, our data also showed enriched gene expression linked to extracellular matrix and immune functions in female control animals compared with male control animals, suggesting molecular sexual dimorphism in sensory ganglia. Finally, our data identified common genes and signaling pathway changes involved in visceral hypersensitivity in both sexes. This study is the first molecular and signaling pathway characterization in the lumbosacral DRG in the context of bladder-origin visceral pain. The sex differences in the molecular profile of lumbosacral DRG in healthy animals and in animals exhibiting visceral pain symptoms suggest sex-specific visceral pain etiology, despite similar symptoms.NEW & NOTEWORTHY This study examined transcriptomics in the lumbosacral DRG in a VEGF-induced visceral pain mouse model. Male and female mice underwent intravesical instillations of VEGF165 or saline. Across the four experimental groups, we found significant sex differences in DRG transcriptome between control animals and VEGF-induced molecular changes, suggesting sex-specific visceral pain mechanisms. These findings provide insight into potential targets for alleviating visceral pain symptoms when considering sex as a biological variable.

The initiating cellular events in cystic fibrosis (CF) hepatobiliary disease are not well characterized, in part due to the lack of accessibility of primary tissues. However, enhanced longevity due to highly effective modulator therapies has generated renewed interest in the key aspects of liver and gallbladder disease, and how these might be treated in people with cystic fibrosis (pwCF). To extend the CF hepatobiliary knowledge base, we performed a transcriptomic analysis of liver and gallbladder development in the wild-type (WT) and CFTR-/- sheep. Bulk RNA was extracted from each tissue at specific timepoints through gestation (from 50 days to term) and used for RNA sequencing (RNA-seq). Differentially expressed genes between the timepoints within each genotype and between WT and CFTR-/- sheep at each timepoint were identified and then used in gene ontology process enrichment analysis to reveal altered biological processes. We find that at the molecular level, the gallbladder in the CFTR-/- animals is both structurally and functionally compromised by midgestation, consistent with the observed microgallbladder phenotype. In the liver, many aspects of differentiation are apparently well-established early in gestation. However, we find functional immaturity in the CFTR-/- liver at term, where genes associated with many key metabolic processes do not show the upregulation seen at term in the WT liver. We also show that the regulatory mechanisms for the CFTR gene in ovine gallbladder cells are highly conserved with those elucidated at the human CFTR locus, further enhancing the relevance of these data to advance understanding of hepatobiliary disease in pwCF.NEW & NOTEWORTHY We use a physiological genomics approach to further understand the etiology of cystic fibrosis gallbladder and liver disease by using a large animal (sheep) model of organ development. We find that the gallbladder in the CFTR-/- animals is both structurally and functionally compromised by midgestation. We also observe functional immaturity in the CFTR-/- liver at term, where genes associated with many key metabolic processes do not show the upregulation seen at term in wild-type liver.