Biology subjects

Hinson, J. T.

Publications and source records attributed to Hinson, J. T..

4 recordsLinked to original sources

bioRxiv2021

Adult fibroblasts retain organ-specific transcriptomic identity

Organ fibroblasts are essential components of homeostatic and diseased tissues. They participate in sculpting the extracellular matrix, sensing the microenvironment and communicating with other resident cells. Recent studies have revealed transcriptomic heterogeneity among fibroblasts within and between organs. To dissect the basis of inter-organ heterogeneity, we compare the gene expression of fibroblasts from different tissues (tail, skin, lung, liver, heart, kidney, gonads) and show that they display distinct positional and organ-specific transcriptome signatures that reflect their embryonic origins. We demonstrate that fibroblasts expression of genes typically attributed to the surrounding parenchyma is established in embryonic development and largely maintained in culture, bioengineered tissues, and ectopic transplants. Targeted knockdown of key organ-specific transcription factors affects fibroblasts functions, with modulation of genes related to fibrosis and inflammation. Our data open novel opportunities for the treatment of fibrotic diseases in a more precise, organ-specific manner.

cell biology↗

bioRxiv2020

SARS-CoV-2 Infects Human Engineered Heart Tissues and Models COVID-19 Myocarditis

Epidemiological studies of the COVID-19 pandemic have revealed evidence of cardiac involvement and documented that myocardial injury and myocarditis are predictors of poor outcomes. Nonetheless, little is understood regarding SARS-CoV-2 tropism within the heart and whether cardiac complications result directly from myocardial infection. Here, we develop a human engineered heart tissue model and demonstrate that SARS-CoV-2 selectively infects cardiomyocytes. Viral infection is dependent on expression of angiotensin-I converting enzyme 2 (ACE2) and endosomal cysteine proteases, suggesting an endosomal mechanism of cell entry. After infection with SARS-CoV-2, engineered tissues display typical features of myocarditis, including cardiomyocyte cell death, impaired cardiac contractility, and innate immune cell activation. Consistent with these findings, autopsy tissue obtained from individuals with COVID-19 myocarditis demonstrated cardiomyocyte infection, cell death, and macrophage-predominate immune cell infiltrate. These findings establish human cardiomyocyte tropism for SARS-CoV-2 and provide an experimental platform for interrogating and mitigating cardiac complications of COVID-19.

immunology↗

bioRxiv2020

Identifying dynamic protein and RNA proximity interaction networks of actinin reveals RNA-binding and metabolic regulatory mechanisms

RationaleActinins are actin cross-linkers that are ubiquitously expressed and harbor mutations in heritable diseases. The predominant cardiac actinin is encoded by ACTN2, which is a core structural component of the sarcomere Z-disk. ACTN2 is required for sarcomere function through complex interactions with proteins involved in sarcomere assembly, cell signaling and transcriptional regulation. However, there remain critical gaps in our knowledge of the complete and dynamic cardiac actinin interactome, which could reveal new insights into sarcomere biology. ObjectiveWe sought to examine the cardiac actinin interactome through sarcomere assembly in human cardiomyocytes. Methods and ResultsWe utilized CRISPR/Cas9, induced pluripotent stem cell technology and BioID to reveal cardiac actinin protein interactions in human cardiomyocytes. We identified 324 cardiac actinin proximity partners, analyzed networks, and studied interactome changes associated with sarcomere assembly. We focused additional studies on unexpected actinin interactions with effectors with RNA-binding functions. Using RNA immunoprecipitation followed by sequencing, we determined that RNA-binding partners uncovered by actinin BioID were bound to gene transcripts with electron transport chain and mitochondrial biogenesis functions. Mammalian two-hybrid studies established that IGF2BP2, an RNA-binding protein associated with type 2 diabetes, directly interacted with the rod domain of actinin through its K Homology domain. IGF2BP2 was necessary for electron transport chain transcript localization to vicinal RNA-binding proteins, mitochondrial mass and oxidative metabolism. IGF2BP2 knockdown also impaired sarcomere function in a cardiac microtissue assay. ConclusionsThis study expands our functional knowledge of cardiac actinin, uncovers new sarcomere interaction partners including those regulated by sarcomere assembly, and reveals sarcomere crosstalk with RNA-binding proteins including IGF2BP2 that are important for metabolic functions.

cell biology↗

bioRxiv2018

A contraction stress model of hypertrophic cardiomyopathy due to thick filament sarcomere mutations

Thick filament sarcomere mutations are the most common cause of hypertrophic cardiomyopathy (HCM), a disorder of heart muscle thickening associated with sudden cardiac death and heart failure, with unclear mechanisms. We engineered an isogenic panel of four human HCM induced pluripotent stem cell (iPSc) models using CRISPR/Cas9, and studied iPSc-derived cardiomyocytes (iCMs) in 3-dimensional cardiac microtissue (CMT) assays that resemble in vivo cardiac architecture and biomechanics. HCM mutations result in hypercontractility in association with prolonged relaxation kinetics in proportion to mutation pathogenicity but not calcium dysregulation. RNA sequencing and protein expression studies identified that HCM mutations result in p53 activation secondary to increased oxidative stress, which results in increased cytotoxicity that can be reversed by p53 genetic ablation. Our findings implicate hypercontractility as an early consequence of thick filament mutations, and the p53 pathway as a molecular marker and candidate therapeutic target for thick filament HCM.

cell biology↗