Biology subjects

Houseright, R. A.

Publications and source records attributed to Houseright, R. A..

3 recordsLinked to original sources

bioRxiv2019

Cell type specific gene expression profiling reveals a role for the complement component C3A in neutrophil migration to tissue damage

Following acute injury, leukocytes rapidly infiltrate into tissues. For efficient recruitment, leukocytes must sense and respond to signals from both from the damaged tissue and from one another. However, the cell type specific transcriptional changes that influence leukocyte recruitment and wound healing have not been well characterized. In this study, we performed a large-scale translating ribosome affinity purification (TRAP) and RNA sequencing screen in larval zebrafish to identify genes differentially expressed by neutrophils, macrophages, and epithelial cells in the context of wounding. We identified the complement pathway and c3a.1, homologous to the C3A component of human complement, as significantly increased in neutrophils in response to a wound. We report that c3a.1-/- zebrafish larvae have impaired neutrophil responses to both tail wounds and localized bacterial infections, as well as increased susceptibility to infection due to a neutrophil-intrinsic function of C3A. We further show that C3A enhances migration of human primary neutrophils to IL-8 and that c3a.1-/- larvae have impaired neutrophil migration in vivo, and a decrease in neutrophil directed migration speed early after wounding. Together, our findings suggest a role for C3A in mediating efficient neutrophil migration to damaged tissues and support the power of TRAP to identify cell-specific changes in gene expression associated with wound-associated inflammation.

immunology↗

bioRxiv2019

DNAJB1-PRKACA fusion induces liver inflammation in zebrafish model of Fibrolamellar Hepatocellular Carcinoma

Fibrolamellar Hepatocellular Carcinoma (FLC) is a rare liver cancer that primarily affects adolescents and young adults. Up to now there is only one identified molecular target responsible for driving the disease, the chimeric protein encoded by DNAJB1-PRKACA (J-PKAca). Immune cells have been identified as key players in liver cancer biology, however the effect of J-PKAca on inflammation in the liver microenvironment is not known. Here we report a new zebrafish model of FLC with non-invasive live imaging capabilities that allows the study of the interactions between immune cells and transformed hepatocytes. We found that overexpression of the dnajb1a-prkcaaa fusion gene specifically in hepatocytes induces early malignancy features in FLC transgenic larvae, such as increased liver and hepatocyte size. In addition, this aberrant form of PKA promotes a pro-inflammatory liver microenvironment by increasing the number of neutrophils and macrophages in the liver area and inducing macrophage polarization to a pro-inflammatory phenotype. Increased caspase-a activity was also found in the liver of FLC transgenic larvae. Importantly, pharmacological inhibition of TNF secretion and caspase-a activity decreased liver size and inflammation. Overall, these findings suggest that inflammation may be an early feature of FLC involved in progression, and that targeting TNFand caspase-1 may be beneficial in treating FLC.

cancer biology↗

bioRxiv2018

High cholesterol diet modulates macrophage polarization and liver inflammation during early hepatocellular carcinoma progression in zebrafish

Diabetes and obesity have been associated with nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) and increased incidence of hepatocellular carcinoma (HCC). Here we use optically transparent zebrafish to visualize liver inflammation and disease progression in a NAFLD/NASH-HCC model. We combined a high-cholesterol diet (HCD) with a transgenic zebrafish HCC model induced by hepatocyte-specific activated {beta}-catenin and found that diet induced an increase in liver size and enhanced angiogenesis and neutrophil infiltration in the liver. Although macrophage number was not affected by diet, HCD induced changes in macrophage morphology and polarization with an increase in liver associated TNF-positive macrophages. Treatment with metformin altered macrophage polarization and reduced liver size in NAFLD/NASH-associated HCC larvae. Moreover, ablation of macrophages limited progression in NAFLD/NASH-associated HCC larvae but not in HCC alone. These findings suggest that HCD alters macrophage polarization and exacerbates the liver inflammatory microenvironment and cancer progression in a zebrafish model of NAFLD/NASH-associated HCC.

cancer biology↗