Biology subjects

Imianowski, C. J.

Publications and source records attributed to Imianowski, C. J..

3 recordsLinked to original sources

bioRxiv2026

immgenT Treg: A Reference Landscape of Regulatory T Cell States in Mice

CD4+FoxP3+ regulatory T cells (Tregs) are central to immunity, tolerance, and tissue homeostasis, yet their extensive heterogeneity lacks a unifying framework. Within the immgenT project, we profiled gene expression, surface markers and TCR clonotypes of mouse Tregs. Using a joint RNA-protein deep generative model, we define the Treg landscape, organized around eight conserved clusters shared across tissues and conditions, with immune context reshaping their relative abundance rather than generating new states, including a prominent circulating effector Treg population enriched in select non-lymphoid tissues. We validate this framework by integrating external datasets from conditions not represented in immgenT and by defining a flow cytometry panel spanning the Treg landscape. Together, immgenT provides a scalable, reusable reference that unifies Treg heterogeneity across tissues and immune challenges.

immunology↗

bioRxiv2024

Hexa-acylated lipopolysaccharides from the gut microbiota enhance cancer immunotherapy responses

Immune checkpoint inhibitors (ICI), such as anti-PD-1, have revolutionized cancer treatment, but they are only effective for a minority of patients. The gut microbiome plays a crucial role in modulating immunotherapy treatment responses, and previous studies correlated lipopolysaccharide (LPS)-producing gut microbes with poorer prognosis. However, LPS from diverse bacterial species have activities ranging from immunostimulatory to inhibitory. By functionally analyzing fecal metagenomes from 112 melanoma patients prior to anti-PD-1 therapy, we found that a subset of LPS-producing bacteria encoding immunostimulatory hexa-acylated LPS was enriched in the microbiomes of clinical responders. We confirmed robust activation of the NF-kB pathway by hexa-acylated LPS in vitro, and this activation was significantly inhibited by penta-acylated LPS in a dose-dependent manner. Importantly, oral administration of hexa-acylated LPS augmented anti-PD-1-mediated anti-tumor immunity in an in vivo mouse model of cancer immunotherapy. Microbiome hexa-acylated LPS may therefore represent an accessible predictor and potential enhancer of clinical anti- PD-1 immunotherapy responses. Statement of significanceFunctional rather than taxonomic profiling of patient gut microbiomes reveals hexa-acylated LPS as a novel biomarker of responsiveness and a targetable pathway for enhancing responses to anti-PD-1, informing future studies and current patient treatment.

microbiology↗

bioRxiv2024

Id1, Spp1 and Pak3 are biomarkers of Smad4 and TGF-β1 dependency in conditional intestinal adenoma, organoids and colorectal cancer.

TGF-{beta} ligand activation suppresses cell growth yet can paradoxically and potently promote cancer invasion and metastasis depending on downstream pathway mutational context. Here, we evaluated the basis of this observation in conditional murine intestinal adenoma models with and without loss of Mothers against decapentaplegic homolog 4 (Smad4), with the aim of identifying TGF-{beta}-BMP-SMAD4 pathway dependent gene expression biomarkers for translational application. Conditional Lgr5-CreERT2 activation in Apcfl/flSmad4fl/flresulted in adenoma formation with recombined homozygote floxed alleles (Apc{Delta}/{Delta}Smad4{Delta}/{Delta}). The adenoma phenotype was discordant, with a reduced small intestinal adenoma burden yet development of large non-metastatic caecal adenoma with nuclear localisation of phospho-Smad2/3. Derived Apc{Delta}/{Delta}Smad4{Delta}/{Delta} adenoma organoids resisted TGF-{beta}1 dose dependent growth arrest and cell death (IC50 534pM) compared to Apc{Delta}/{Delta}Smad4+/+ (IC 24pM). TGF-{beta}1 (390pM) modified adenoma mRNA expression (bulk RNA-Seq) most significantly for Id1low and Spp1high in Apc{Delta}/{Delta}Smad4{Delta}/{Delta}. Single cell RNAseq of caecal adenoma identified expansion of Lgr5low, Pak3high and Id1low progenitor populations in Apc{Delta}/{Delta}Smad4{Delta}/{Delta}. Of the 76 Smad4 and TGF-{beta}1 dependent genes identified in adenoma organoids, 7 human equivalent genes were also significantly differentially expressed in colorectal cancer, including ID1low, SPP1high and PAK3high that also correlated with poorer survival (TCGA cohorts). Murine conditional models identified Smad4 loss of function mRNA expression biomarkers that require further evaluation as functional classifiers of colorectal cancer subtypes.

cancer biology↗