Yi, M. | bioRxiv Science

bioRxiv2019

Multispectral Imaging Differentiates Unique Macrophage Profiles in Patients with Distinct Chronic Liver Diseases

Intrahepatic macrophages influence the composition of the microenvironment, host immune response to liver injury, and development of fibrosis. Compared to stellate cells, the role of intrahepatic macrophages in the development of fibrosis remains ill defined. Multispectral imaging allows detection of multiple markers in situ in human formalin-fixed, paraffin-embedded tissue. This cutting-edge technology is ideal for analyzing human liver tissues since it allows spectral unmixing of fluorophore signals, subtraction of auto-fluorescence, and preserves architecture and the in vivo hepatic milieu. We analyzed resident Kupffer cells (CD68+), monocyte-derived macrophages (Mac387+), pro-fibrogenic macrophages (CD163+), and co-expression of pro-inflammatory (CD14) and anti-inflammatory (CD16) markers in liver biopsies from patients with hepatitis C virus (HCV) and different stages of fibrosis. Liver biopsies with advanced fibrosis showed increased accumulation of CD163+, MAC387+ and CD68+ macrophages in the portal tracts when compared to those with minimal fibrosis. Imaging software generated t-distributed stochastic neighbor embedding (t-SNE) plots and phenotype matrices that facilitated comparison of macrophage profiles. These included monocyte-derived (CD68+/Mac387+) and pro-fibrotic/anti-inflammatory (CD163+/CD16+) phenotypes. We established that the utility of this platform could be extended to liver biopsies from patients with other chronic liver diseases including nonalcoholic steatohepatitis and autoimmune hepatitis. Each disease exhibited a unique profile after spectral imaging analysis and this platform holds the potential to identify patients predisposed to progressive liver disease based on the macrophage composition. In summary, spectral imaging is a powerful tool that enables analysis of macrophage profiles in different types of chronic liver diseases and has potential to change the manner in which we evaluate liver biopsies leading to more personalized treatment strategies.

pathology↗

bioRxiv2019

First description of the sexual stage of Venturia effusa, causal agent of pecan scab

Venturia effusa, cause of pecan scab, is the most prevalent disease of pecan in the southeastern USA; epidemics of the disease regularly result in economic losses to the pecan industry. Recent characterization of the mating type distribution revealed the frequency of the MAT idiomorphs are in equilibrium at various spatial scales, indicative of regular sexual recombination. However, the occurrence of the sexual stage of V. effusa has never been observed, and the pathogen was previously believed to rely entirely on asexual reproduction. To explore the existence of a sexual cycle, we paired opposite mating types on oatmeal culture media. In initial experiments, cultures were incubated at 24 C for 2 mo for hyphal interactions to occur between mating types and then maintained at 4 C for 4 mo. Immature pseudothecia were initially observed but following exposure to a 12 h photoperiod for 2 weeks at 24 C, asci and ascospores developed. Further experiments explored the effect of time on pseudothecial development with 4 mo at 4 C as the optimal requirement. The results of this study demonstrate the heterothallic nature of V. effusa. Following experiments investigated progeny from a sexual cross of an albino and a wild-type isolate. Evaluation of isolate pigmentation, mating type, and multilocus genotyping of single ascospore progeny provided evidence that recombination occurred within the sexual crosses. The impact of determining the source of the overwintering ascostroma will aid in management decisions to reduce the primary inoculum in the disease cycle.

pathology↗