Biology subjects

Zurakowski, D.

Publications and source records attributed to Zurakowski, D..

5 recordsLinked to original sources

bioRxiv2025

An endothelial specific mouse model for the capillary malformation mutation Gnaq p.R183Q

Capillary malformation (CM) is a congenital, non-hereditary lesion composed of enlarged and tortuous blood vessels. CM is associated with a somatic GNAQ p.R183Q activating mutation in endothelial cells (EC). Cutaneous CMs are present in 1/300 infants and in 55-70% of CM cases soft tissue overgrowth is observed. Pharmacotherapy for CM does not exist. Here we report a conditional mouse model allowing the simultaneous tissue specific expression of GNAQ p.R183Q and GFP from the R26 locus (R26GT-Gnaq-GFP). We show that expression of GNAQ p.R183Q in ECs results in vascular malformations with features similar to human CM lesions. GNAQ p.R183Q expression during embryonic development (Tg-Cdh5Cre) resulted in a severe vascular phenotype, lethal by embryonic (E) 16.5. Induction of mutant GNAQ expression in ECs at postnatal (P) day 1 (Tg-Cdh5CreER) led to tortuous and enlarged blood vessels, most noticeable in the intestines. GNAQ p.R183Q/GFP expressing ECs co-localized with lesions and displayed increased proliferation. Mutant ECs had abnormal mural cell coverage and abnormal pericellular extracellular matrix deposition, which was confirmed in human CM samples. Similar to human CM they displayed strong expression of the tip cell marker ESM1 and increased ANGPT2 expression. In conclusion, GNAQ p.R183Q expression in murine ECs causes vascular malformations supporting the causality of the mutation for CM. The lesions recapitulate multiple features of human CM, making the mouse model suitable for the preclinical testing of future CM pharmacotherapy.

cell biology↗

bioRxiv2024

Dispersion indices for universal quantification of fluorescently-labelled subcellular structure spatial distributions

Image analysis of subcellular structures and biological processes relies on specific, context-dependent pipelines, which are labor-intensive, constrained by the intricacies of the specific biological system, and inaccessible to broader applications. Here we introduce the application of dispersion indices, a statistical tool traditionally employed by economists, to analyze the spatial distribution and heterogeneity of subcellular structures. This computationally efficient high-throughput approach, termed GRID (Generalized Readout of Image Dispersion), is highly generalizable, compatible with open-source image analysis software, and adaptable to diverse biological scenarios. GRID readily quantifies diverse structures and processes to include autophagic puncta, mitochondrial clustering, and microtubule dynamics. Further, GRID is versatile, applicable to both 2D cell cultures and 3D multicellular organoids, and suitable for high-throughput screening and performance metric measurements, such as half-maximal effective concentration (EC50) values. The approach enables mechanistic analysis of critical subcellular structure processes of relevance for diseases ranging from metabolic and neuronal diseases to cancer as well as a first-pass screening method for identifying biologically active agents for drug discovery. Statement of SignificanceCurrent methods for image analysis in microscopy are tailored to specific biological contexts, which creates challenges in implementation and efficiency for researchers studying a diverse range of subcellular processes. Our application of dispersion indices, traditionally used in economics, offers a universal framework for high throughput quantification of biological structures, enabling easier and more consistent analysis across various biological contexts. By transforming pixel intensity and count into meaningful statistical measures, our method simplifies the quantification of subcellular structures such as autophagic puncta, microtubule dynamics, and mitochondrial clustering. This approach accelerates the quantitative analysis of sub-cellular processes in disease as well as imaged-based drug discovery. Classification: Bioengineering, Cell Biology, Applied Biological Sciences

cell biology↗

bioRxiv2022

Multicomponent Pseudomonas aeruginosa vaccines eliciting Th17 cells and functional antibody responses confer enhanced protection against experimental acute pneumonia in mice

The Gram-negative pathogen Pseudomonas aeruginosa is a common cause of pneumonia in hospitalized patients. Its increasing antibiotic resistance and widespread occurrence present a pressing need for vaccines. We previously showed that a P. aeruginosa type III secretion system protein, PopB elicits a strong Th17 response in mice after intranasal (IN) immunization and confers antibody-independent protection against pneumonia in mice. In the current study, we evaluated the immunogenicity and protective efficacy in mice of the combination of PopB (purified with its chaperone protein PcrH) and OprF/I, an outer membrane hybrid fusion protein, compared to immunization with the proteins individually either by the intranasal (IN) or subcutaneous (SC) routes. Our results show that after vaccination, a Th17 recall response from splenocytes was detected only in mice vaccinated with PopB/PcrH, either alone or in combination with OprF/I. Mice that were immunized with the combination of PopB/PcrH and OprF/I had enhanced protection in an acute lethal P. aeruginosa pneumonia model, regardless of vaccine route, compared to the mice vaccinated the with either alone or adjuvant control. Immunization generated IgG titers against the vaccine proteins and whole P. aeruginosa cells. Interestingly, none of these antisera had opsonophagocytic killing activity, but antisera from mice immunized with vaccines containing OprF/I had the ability to block IFN-{gamma} binding to OprF/I, a known virulence mechanism. Hence, vaccines combining PopB/PcrH with OprF/I that elicit functional antibodies lead to a broadly and potently protective vaccine against P. aeruginosa pulmonary infections.

immunology↗

bioRxiv2019

Pain Stickiness in Complex Regional Pain Syndrome: A role for the Nucleus Accumbens

Some individuals with chronic pain experience improvement in their pain with treatment, whereas others do not. The neurobiological reason is unclear, but an understanding of brain structure and functional patterns may provide insights into pains responsivity to treatment. In this investigation, we used magnetic resonance imaging (MRI) techniques to determine grey matter density alterations on resting functional connectivity (RFC) strengths between pain responders and nonresponders. Brain metrics of pediatric patients at admission to an intensive pain rehabilitative treatment program were evaluated. Pain responders reported significant pain improvement at discharge and/or follow-up whereas nonresponders reported no improvements, increases in pain, or emergence of new pain symptoms. The pain (responder/nonresponder) groups were compared with pain-free healthy controls to examine predictors of pain responder status via brain metrics. Our results show: (1) on admission, pain nonresponders had decreased grey matter density (GMD) within the nucleus accumbens (NAc) and reduced RFC strength between the NAc and the dorsolateral prefrontal cortex vs. responders; (2) Connectivity strength was positively correlated with change in pain intensity from admission to discharge; (3) Compared with pain-free controls, grey matter and RFC differences emerged only among pain nonresponders; and (4) Using a discriminative model, combining GMD and RFC strengths assessed at admission showed the highest prediction estimate (87%) on potential for pain improvement, warranting testing in a de novo sample. Taken together, these results support the idea that treatment responsiveness on pain is underpinned by concurrent brain structure and resting brain activity.

neuroscience↗

bioRxiv2017

Transit and integration of extracellular mitochondria in human heart cells

Tissue ischemia adversely affects the function of mitochondria, which results in impairment of oxidative phosphorylation and compromised recovery of the affected organ. The impact of ischemia on mitochondrial function has been most extensively studied in the heart because of the morbidity and mortality associated with injury to this organ. Because conventional methods to preserve cell viability and function following an ischemic injury are limited in their efficacy, we developed a unique approach to protect the heart by transplanting respiration-competent mitochondria isolated from a non-ischemic tissue to the ischemic region. Our experiments in animals have shown that transplantation of isolated mitochondria to injured heart tissue leads to decreases in cell death, increases in energy production, and improvements in contractile function. We also discovered that exogenously-derived mitochondria injected or perfused into ischemic hearts were readily internalized by cardiac cells through actin-dependent endocytosis. Here, we describe the use of three-dimensional super-resolution microscopy and transmission electron microscopy to determine the intracellular fate of exogenous mitochondria in non-dividing human iPS-derived cardiomyocytes and dividing primary human cardiac fibroblasts. We show isolated mitochondria are internalised in human cardiac cells within minutes and then transported to endosomes and lysosomes. The majority of exogenous mitochondria escape from these compartments and fuse with the endogenous mitochondrial network, while some organelles are degraded through hydrolysis. Understanding this process may guide the development of treatments directed at replacing or augmenting impaired mitochondria in ischemic tissues and provide new options to rejuvenate dysfunctional mitochondria in a wide range of human diseases and disorders.

cell biology↗