Biology subjects

Pitt, D.

Publications and source records attributed to Pitt, D..

4 recordsLinked to original sources

bioRxiv2024

AutoMorFi: Automated Whole-image Morphometry in Fiji/ImageJ for Diverse Image Analysis Needs

Running on the highly popular and accessible ImageJ/Fiji platform for biological image analysis, we have established AutoMorFi as a streamlined interface for automated whole-image morphometric analysis that generates at least 47 measurements per cell or object in under 1 minute. We performed multiple validated cluster and principal component analyses on nonredundant morphometric parameters derived from AutoMorFi for various cell types, objects, and organisms. We used images of rodent macrophages, human postmortem brain tissues from multiple sclerosis (MS) and Alzheimers disease (AD) patients, iPSC/animal models for Downs syndrome and autism spectrum disorder (ASD), and organisms such as sea anemone and corals. AutoMorFis adaptability extends across diverse imaging modalities including brightfield, confocal, or widefield fluorescence microscopy as well as underwater photography. Due to its unlimited and unbiased sampling across any image and high potential for modification and customization, using AutoMorFi has led to the discovery of new distinguishing features in previously studied cell types and organisms as well as the development of rapid diagnostic approaches. AutoMorFi represents a transformative tool that will accelerate morphometric analysis and offer broad relevance in biological studies.

cell biology↗

bioRxiv2019

The landscape of myeloid and astrocyte phenotypes in acute multiple sclerosis lesions

Activated myeloid cells and astrocytes are the predominant cell types in active multiple sclerosis (MS) lesions. Both cell types can adopt diverse functional states that play critical roles in lesion formation and resolution. In order to identify phenotypic subsets of myeloid cells and astrocytes, we profiled acute MS lesions with thirteen glial activation markers using imaging mass cytometry (IMC), a method for multiplexed labeling of histological sections. In a demyelinating lesion, we found multiple distinct myeloid and astrocyte phenotypes that populated separate lesion zones. In a post-demyelinating lesion, phenotypes were less distinct and more uniformly distributed. In both lesions cell-to-cell interactions were not random, but occurred between specific glial subpopulations and lymphocytes. Finally, we demonstrated that myeloid, but not astrocyte phenotypes were activated along a lesion rim-to-center gradient, and that marker expression in glial cells at the lesion rim was driven more by cell-extrinsic factors than in cells at the center. This proof-of-concept study demonstrates that highly multiplexed tissue imaging, combined with the appropriate computational tools, is a powerful approach to study heterogeneity, spatial distribution and cellular interactions in the context of MS lesions. Identifying glial phenotypes and their interactions at different lesion stages may provide novel therapeutic targets for inhibiting acute demyelination and low-grade, chronic inflammation.

immunology↗

bioRxiv2019

Differential expression of the T cell inhibitor TIGIT in Glioblastoma and Multiple Sclerosis

To identify co-inhibitory immune pathways important in the brain, we hypothesized that comparison of T cells in lesions from patients with MS with tumor infiltrating T cells (TILs) from patients with GBM may reveal novel targets for immunotherapy. Focusing on PD-1 and TIGIT, we found that TIGIT and its ligand CD155 were highly expressed on GBM TILs but were near-absent in MS lesions, while lymphocytic expression of PD-1/PDL-1 was comparable. TIGIT was also upregulated in peripheral lymphocytes in GBM, suggesting recirculation of TILs. These data raise the possibility that anti-TIGIT therapy may be beneficial for patients with glioblastoma.

immunology↗

bioRxiv2017

Enhanced Astrocyte Responses are Driven by a Genetic Risk Allele Associated with Multiple Sclerosis

Epigenetic annotation studies of genetic risk variants for multiple sclerosis (MS) implicate dysfunctional lymphocytes in MS susceptibility; however, the role of central nervous system (CNS) cells remains unclear. We investigated the effect of the risk variant, rs7665090G, located near NFKB1, on astrocytes. We demonstrated that chromatin is accessible at the risk locus, a prerequisite for its impact on astroglial function. The risk variant was associated with increased NF-{kappa}B signaling and target gene expression driving lymphocyte recruitment in cultured human astrocytes and astrocytes within MS lesions, and with increased lesional lymphocytic infiltrates. In MS patients, the risk genotype was associated with increased lesion volumes on MRI. Thus, we established that the rs7665090G variant perturbs astrocyte function resulting in increased CNS access for peripheral immune cells. MS may thus result from variant-driven dysregulation of the peripheral immune system and the CNS, where perturbed CNS cell function aids in establishing local autoimmune inflammation.\n\nOne Sentence SummaryThe NF-{kappa}B relevant multiple sclerosis risk variant, rs7665090G, drives astrocyte responses that promote lesion formation.

neuroscience↗