Biology subjects

Silver, A.

Publications and source records attributed to Silver, A..

8 recordsLinked to original sources

bioRxiv2025

Treatment Resistant Persister Cells Exploit Macrophage Lipid Metabolism to Sustain Glioblastoma Growth

Glioblastoma (GBM) displays pronounced intratumoral heterogeneity, posing significant challenges to understanding its biology and developing effective treatments. Using spatial multi-omics, in vivo functional assays, and systems-level analysis, we delineate the diverse metabolic and immune architecture of GBM. We identify a lipid-dependent lineage of treatment-resistant persister cells (TRPCs) that engage tumor-associated macrophages (TAMs) in a spatially organized, metabolically specialized crosstalk. TRPCs co-opt CCR2, CSF1R, CD163+ TAMs for lipid scavenging and acquisition, promoting a pro-tumorigenic and immunosuppressive microenvironment. This cooperative axis is critically dependent on lipid chaperones like FABPs, whose targeting disrupts TAM recruitment, remodels immune composition, and suppresses tumor growth. Retrospective clinical analyses reveal that elevated TRPC-associated transcriptome may serve as stratification criteria to identify patients benefiting from lipid-lowering therapies like statins. Our findings uncover a targetable immunometabolic circuit between TRPCs and TAMs and support the development of precision therapies that disrupt lipid-fueled tumor-immune cooperation in GBM. In briefTreatment-resistant persister cells (TRPCs) in glioblastoma spatially engage TAMs to facilitate lipid transfer, thereby sustaining tumor growth and promoting immune evasion. Targeting this TRPC-TAM metabolic axis reprograms the immunosuppressive microenvironment and improves therapeutic outcomes, revealing a clinically actionable metabolic vulnerability with potential for precision immune-metabolic interventions in GBM. HighlightsO_LIGBM exhibits spatially resolved heterogeneity revealing correlative metabolic and immune micro-niches C_LIO_LITRPC lineage promotes a pro-tumorigenic and immunosuppressive microenvironment by recruiting lipid-specialized TAMs C_LIO_LITRPC lineage hijacks TAMs for metabolic support via stimulating lipid transfer and acquisition C_LIO_LIDisruption of the TRPC-TAM lipid axis, including through FABP3 targeting, reprograms the immune landscape, limits TAM recruitment, and impairs tumor progression C_LIO_LITRPC lineage and associated micro-niche transcriptomic profiles can serve as criteria for patient stratification and identification of responders to lipid-lowering therapies, such as statins C_LI

cancer biology↗

bioRxiv2024

Plasma membrane transporter Progressive Ankylosis Protein Homolog (ANKH/Ankh) mediates senescence-derived extracellular citrate and is regulated by DNA damage, inflammation and ageing

A considerable body of recent evidence supports citrate transport as a major regulator of organismal lifespan and healthspan. Citrate accumulates outside senescent cells in vitro and in vivo. However, the detailed mechanism of senescent cell extracellular citrate (EC) accumulation is not clear. We show here that EC is partially mediated by a newly described plasma membrane citrate transporter ANKH/SLC62A1 (progressive human ankylosis - ANKH) in senescent fibroblasts. Analogous to interleukin 6 (IL-6), EC and/or ANKH are regulated by telomere dysfunction, the p38 mitogen-activated kinase axis, transforming growth factor beta and p53, but in contrast not by steroids, sodium butyrate, or Ataxia Telangiectasia Mutated (ATM). ANKH was upregulated in other senescent cell types relevant to ageing but not keratinocytes. In contrast, EC and ANKH were inhibited in dividing and senescent fibroblasts by interleukin 1 (IL-1) in parallel with increased IL-6 secretion. Loss- and gain of function mutations of ANKH/Ank are associated with disease and interestingly, Ank is also downregulated in both aged mouse liver and brain tissues in parallel with increased senescence markers and several cytokines, suggesting that inflammatory cytokines could inhibit EC production in vivo. These data identify ANKH/Ank as a novel regulator of senescence-derived EC in both humans and mice. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/609895v3_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@1eed642org.highwire.dtl.DTLVardef@1349040org.highwire.dtl.DTLVardef@1ea867aorg.highwire.dtl.DTLVardef@22d251_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2024

Get to know your neighbors with a SNAQ™: A framework for single cell spatial neighborhood analysis in immunohistochemical images

MotivationAnalyzing the local microenvironment of tumor cells can provide significant insights into their complex interactions with their cellular surroundings, including immune cells. By quantifying the prevalence and distances of certain immune cells in the vicinity of tumor cells through a neighborhood analysis, patterns may emerge that indicate specific associations between cell populations. Such analyses can reveal important aspects of tumor-immune dynamics, which may inform therapeutic strategies. This method enables an in-depth exploration of spatial interactions among different cell types, which is crucial for research in oncology, immunology, and developmental biology. ResultsWe introduce an R Markdown script called SNAQTM (Single-cell Spatial Neighborhood Analysis and Quantification), which conducts a neighborhood analysis on immunofluorescent images without the need for extensive coding knowledge. As a demonstration, SNAQTM was used to analyze images of pancreatic ductal adenocarcinoma. Samples stained for DAPI, PanCK, CD68, and PD-L1 were segmented and classified using QuPath. The resulting CSV files were exported into RStudio for further analysis and visualization using SNAQTM. Visualizations include plots revealing the cellular composition of neighborhoods around multiple cell types within a customizable radius. Additionally, the analysis includes measuring the distances between cells of certain types relative to others across multiple regions of interest. Availability and implementationThe R Markdown files that comprise the SNAQTM algorithm and the input data from this paper are freely available on the web at https://github.com/AryehSilver1/SNAQ. Visual Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=70 SRC="FIGDIR/small/606539v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@1cda240org.highwire.dtl.DTLVardef@157280forg.highwire.dtl.DTLVardef@1072cf8org.highwire.dtl.DTLVardef@1964e0_HPS_FORMAT_FIGEXP M_FIG C_FIG Created with BioRender.com.

bioinformatics↗

bioRxiv2024

KR158 spheres harboring slow-cycling cells recapitulate GBM features in an immunocompetent system

Glioblastoma (GBM) poses a significant challenge in clinical oncology due to its aggressive nature, heterogeneity, and resistance to therapies. Cancer stem cells (CSCs) play a critical role in GBM, particularly in treatment-resistance and tumor relapse, emphasizing the need to comprehend the mechanisms regulating these cells. Also, their multifaceted contributions to the tumor-microenvironment (TME) underline their significance, driven by their unique properties. This study aimed to characterize glioblastoma stem cells (GSCs), specifically slow-cycling cells (SCCs), in an immunocompetent murine GBM model to explore their similarities with their human counterparts. Using the KR158 mouse model, we confirmed that SCCs isolated from this model exhibited key traits and functional properties akin to human SCCs. KR158 murine SCCs, expanded in the gliomasphere assay, demonstrated sphere forming ability, self-renewing capacity, positive tumorigenicity, enhanced stemness and resistance to chemotherapy. Together, our findings validate the KR158 murine model as a framework to investigate GSCs and SCCs in GBM-pathology, and explore specifically the SCC-immune system communications, understand their role in disease progression, and evaluate the effect of therapeutic strategies targeting these specific connections.

cancer biology↗

bioRxiv2023

A rapid method for generating transplantable and biologically responsive colonic tissue from human induced pluripotent stem cells.

BackgroundThe colonic mucosa consists of cell populations derived from multiple lineages. Induced pluripotent stem cells (iPSCs) are capable of generating large numbers of differentiated cells from any lineage. Thus, iPSCs are highly versatile for derivation of intestinal cells for generation of colonic mucosal tissue for clinical and biological applications. ObjectiveWe set out to create a human iPSC (hiPSC) multi-lineage co-differentiation platform capable of generating colonic mucosal tissue in vitro. DesignWe used hiPSCs and designed a differentiation protocol consisting of small molecules and recombinant growth factors to generate multiple cell lineages. Cells were seeded onto collagen hydrogels (forming colonic patches - CoPs) and modulated with multiple growth factors important in intestinal biology. CoPs were transplanted into immunosuppressed mice. Generated cells and tissues were profiled with transcriptomic analysis. ResultshiPSC co-differentiation led to multiple intestinal epithelial, mesenchymal and endothelial cell populations. Seeded onto collagen scaffolds these cells created CoPs, which were transplanted into mouse subcutis. Engrafted CoPs developed into normal-looking colonic mucosa containing epithelial crypts (with enterocytes, goblet cells and neuroendocrine cells), multiple lamina propria-resident stromal populations and muscularis mucosae smooth muscle. They anastomosed to murine vasculature and maintained in-vitro for several weeks. We demonstrated that CoPs respond to known signalling pathways important in colonic mucosal biology and fibrogenesis, showing potential to provide a complex model of colonic pathobiology. ConclusionThis platform could offer an accurate model of intestinal pathobiology, supply cells for regenerative cell therapies to treat intestinal disease, and provide therapeutic autologous grafts to repair damaged colon.

cell biology↗

bioRxiv2023

Single cell sequencing data identify distinct B cell and fibroblast populations in stricturing Crohns disease

We used human full thickness Crohns disease (CD) small bowel resection specimens and single cell RNA sequencing to identify potential therapeutic targets for stricturing (S)CD. Using an unbiased approach, 16 cell lineages were assigned within 14,539 sequenced cells from patient-matched SCD and non-stricturing (NSCD) preparations. SCD and NSCD contained identical cell types. Amongst immune cells, B cells and plasma cells were selectively increased in SCD samples. B cell subsets suggested formation of tertiary lymphoid tissue in SCD and compared with NSCD there was an increase in IgG, and a decrease in IgA plasma cells, consistent with their potential role in CD fibrosis. Two Lumican-positive fibroblast subtypes were identified and subclassified based on expression of selectively enriched genes as fibroblast clusters (C)12 and C9. Cells within these clusters expressed the profibrotic genes Decorin (C12) and JUN (C9). C9 cells expressed ACTA2; ECM genes COL4A1, COL4A2, COL15A1, COL6A3, COL18A1 and ADAMDEC1; LAMB1 and GREM1. GO and KEGG Biological terms showed extracellular matrix, stricture organisation and regulation of WNT pathway genes are associated with the C12 and C9 gene sets. Trajectory and differential gene analysis of C12 and C9 identified four sub-clusters. Intra sub-cluster gene analysis detected co-regulated gene modules that aligned along predicted pseudotime trajectories and identified CXCL14 and ADAMDEC1 as key module markers. Our findings support further investigation of fibroblast heterogeneity and interactions with local and circulating immune cells at earlier time points in fibrosis progression. Breaking these interactions by targeting one or other population may improve therapeutic management for SCD.

genomics↗

bioRxiv2020

NOVEL NUCLEAR ROLE OF HDAC6 IN PROGNOSIS AND THERAPEUTIC TARGET FOR COLORECTAL CANCER

Histone deacetylase 6 (HDAC6) inhibition is a potential treatment of a wide range of cancer types via the acetylation of diverse proteins in the cytoplasm. However, the regulation of histone acetylation and the maintenance of higher-order chromatin structure remains unidentified. Here, we investigated the effect of selective inhibition of HDAC6 by histone acetylation, chromatin relaxation assays, co-immunoprecipitation, acetylome peptide array and in vivo RNA microarray. Our data shows that nuclear HDAC6 physically interacts with the Histone 4 lysine 12 residue, and that HDAC6 inhibition increases acetylation specifically at this residue in several cancer types. Inhibition induces major chromatin structure modulation, but has no equivalent effect on knockout HDAC6-/- MEF cells. We identified several novel HDAC6-deacetylated substrates and high expression of HDAC6 in colorectal cancer (CRC) tissue association with reduced levels of H4K12ac and independent of the key CRC driver mutations, but positively associated with EGFR expression. Furthermore, in vivo HDAC6 inhibition induces significant tumor regression in a CRC xenograft mice model with significant changes in the expression of functional nuclear genes. We also demonstrated that a DNA damaging agent in combination with selective HDAC6 inhibition is effective and acts synergistically, inducing chromatin relaxation and increased cell death in CRC cells. CRC tissues (Normal versus tumor; n=58 matched pairs) together with TCGA data analysis of 467 CRC patients showed that high HDAC6 expression is associated with metastasis, overall and disease-free survival, and is an independent risk factor of CRC stage progression. Our findings designate a new role for nuclear HDAC6 both in cancer prognosis and as a new therapeutic target for CRC and other types of cancer. HighlightHistone deacetylases 6 activity; Chromatin relaxation; Histone modifications; Gene array; DOX: doxorubicin; OXA: oxaliplatin; 5-FU: fluorouracil; Ac: acetylation; MNase: Micrococal nuclease.

cancer biology↗

bioRxiv2020

Persistence of the ground beetle (Coleoptera: Carabidae) microbiome to diet manipulation

Host-associated microbiomes can play important roles in the ecology and evolution of their insect hosts, but bacterial diversity in many insect groups remains poorly understood. Here we examine the relationship between host environment, host traits, and microbial diversity in three species in the ground beetle family (Coleoptera: Carabidae), a group of roughly 40,000 species that synthesize a wide diversity of defensive compounds. This study found that the ground beetle microbiome is consistent across different host food sources. We used 16S amplicon sequencing to profile three species that are phylogenetically distantly related, trophically distinct, and whose defensive chemical secretions differ: Anisodactylus similis LeConte, 1851, Pterostichus serripes (LeConte, 1875), and Brachinus elongatulus Chaudoir, 1876. Wild-caught beetles were compared to individuals maintained in the lab for two weeks on carnivorous, herbivorous, or starvation diets. Soil environment but not diet had a significant effect on bacterial diversity and composition. The three carabid species have patterns of microbial diversity similar to those previously found in other insect hosts. Metagenomic samples from two highly active tissue types -- guts, and pygidial gland secretory cells (which produce defensive compounds) -- were processed and sequenced separately from those of the remaining body. The observed similarity of the pygidial gland secretory cell microbiome across hosts suggests the possibility that it may be a conserved community, possibly due to functional interactions related to defensive chemistry. These results provide a baseline for future studies of the role of microbes in the diversification of defensive chemical biosynthesis in carabids.

ecology↗