Biology subjects

Rutkowski, M. R.

Publications and source records attributed to Rutkowski, M. R..

3 recordsLinked to original sources

bioRxiv2023

Non-invasive Analysis of Peptidoglycan from Living Animals

The role of the intestinal microbiota in host health is increasingly revealed in its contributions to disease states. The host-microbiome interaction is multifactorial and dynamic. One of the factors that has recently been strongly associated with host physiological responses is peptidoglycan from bacterial cell walls. Peptidoglycan from gut commensal bacteria activate peptidoglycan sensors in human cells, including the Nucleotide-binding oligomerization domain containing protein 2 (NOD2). When present in the gastrointestinal tract, both the polymeric form (sacculi) and de-polymerized fragments can modulate host physiology, including checkpoint anticancer therapy efficacy, body temperature and appetite, and postnatal growth. To leverage this growing area of biology towards therapeutic prescriptions, it will be critical to directly analyze a key feature of the host-microbiome interaction from living hosts in a reproducible and non-invasive way. Here we show that metabolically labeled peptidoglycan/sacculi can be readily isolated from fecal samples collected from both mice and humans. Analysis of fecal samples provided a non-invasive route to probe the gut commensal community including the metabolic synchronicity with the host circadian clock. Together, these results pave the way for non-invasive diagnostic tools to interrogate the causal nature of peptidoglycan in host health and disease.

microbiology↗

bioRxiv2022

Non-invasive Fluorescence Imaging of Gut Commensal Bacteria in Live Mice

In mammals, gut commensal microbiota interact extensively with the host and the same interactions can be dysregulated in diseased states. The development of methods to monitor gut microbiota in vivo can lead to improved foundational understanding of the biological events underpinning these interactions. The current standard for non-invasive monitoring of gut bacteria entails classification by 16S rRNA sequencing from fecal samples. This method has many advantages but also has serious limitations, especially for monitoring dynamic changes in the gut of live animals. In recent years, several imaging techniques have been widely adopted that afford non-invasive assessment of animal subjects - most notably in cancer biology; however, these technical gains have not translated to the imaging of gut bacterial communities. Herein, we describe a method to non-invasively image commensal bacteria based on the specific metabolic labeling of bacterial cell walls to illuminate the gut bacteria of live mice. This tagging strategy may additionally provide unprecedented insight into cell wall turnover of gut commensals, which has implications for bacterial cellular growth and division, in a live animal.

microbiology↗

bioRxiv2021

Reciprocal interactions between the gut microbiome and mammary tissue mast cells promote metastatic dissemination of HR+ breast tumors

Establishing commensal dysbiosis, defined as an inflammatory gut microbiome with low biodiversity, prior to breast tumor initiation, enhances early dissemination of hormone-receptor positive (HR+) mammary tumor cells. Here, we sought to define mammary tissue mediators of dysbiosis-induced tumor dissemination. We found that commensal dysbiosis increased both the frequency and profibrogenicity of mast cells in the mammary tissue, a phenotypic change that persisted after tumor implantation. Fibroblast activation and tissue remodeling associate with enhanced breast tumor metastasis. We employed pharmacological and adoptive transfer approaches to demonstrate that mammary tissue mast cells from dysbiotic animals enhances dissemination of HR+ tumor cells. Collagen levels in mammary tissues from HR+ breast cancer patients correlated with mast cell abundance, suggesting clinical relevance of mast cell-mediated fibroblast activation. Together, these data demonstrate that a gut-mast cell axis exists that induces fibroblast activation and orchestrates early dissemination of HR+ breast tumors. SignificanceOur study defines the mechanism by which an inflammatory gut microbiome facilitates HR+ breast tumor cell dissemination. We establish that gut commensal dysbiosis triggers mammary tissue mast cells to facilitate early metastatic dissemination. These findings highlight a novel gut microbiome-innate immune cell axis involved in negative breast cancer outcomes.

cancer biology↗