Computational tools for automated histological image analysis and quantification in cardiac tissue.

Image processing and quantification is a routine and important task across disciplines in biomedical research. Understanding the effects of disease on the tissue and organ level often requires the use of images, however the process of interpreting those images into data which can be tested for significance is often time intensive, tedious and prone to inaccuracy or bias. When working within resource constraints, these different issues often present a trade-off between time invested in analysis and accuracy. To address these issues, we present two novel open source and publically available tools for automated analysis of histological cardiac tissue samples: •Automated Fibrosis Analysis Tool (AFAT) for quantifying fibrosis; and•Macrophage Analysis Tool (MAT) for quantifying infiltrating macrophages.

ßIV-Spectrin regulates STAT3 targeting to tune cardiac response to pressure overload.

Heart failure (HF) remains a major source of morbidity and mortality in the US. The multifunctional Ca2+/calmodulin-dependent kinase II (CaMKII) has emerged as a critical regulator of cardiac hypertrophy and failure, although the mechanisms remain unclear. Previous studies have established that the cytoskeletal protein ßIV-spectrin coordinates local CaMKII signaling. Here, we sought to determine the role of a spectrin-CaMKII complex in maladaptive remodeling in HF. Chronic pressure overload (6 weeks of transaortic constriction [TAC]) induced a decrease in cardiac function in WT mice but not in animals expressing truncated ßIV-spectrin lacking spectrin-CaMKII interaction (qv3J mice). Underlying the observed differences in function was an unexpected differential regulation of STAT3-related genes in qv3J TAC hearts. In vitro experiments demonstrated that ßIV-spectrin serves as a target for CaMKII phosphorylation, which regulates its stability. Cardiac-specific ßIV-spectrin-KO (ßIV-cKO) mice showed STAT3 dysregulation, fibrosis, and decreased cardiac function at baseline, similar to what was observed with TAC in WT mice. STAT3 inhibition restored normal cardiac structure and function in ßIV-cKO and WT TAC hearts. Our studies identify a spectrin-based complex essential for regulation of the cardiac response to chronic pressure overload. We anticipate that strategies targeting the new spectrin-based "statosome" will be effective at suppressing maladaptive remodeling in response to chronic stress.