Biology subjects

Macedo, R.

Publications and source records attributed to Macedo, R..

5 recordsLinked to original sources

bioRxiv2025

Conserved Landscape of Chemokine Receptor Co-expression Defines the Functional States of CD8+ T Cells in Melanoma

Cancer immunotherapies, from checkpoint blockade to adoptive cell therapies like tumor-infiltrating lymphocytes (TILs), have revolutionized cancer treatment but are limited by variable efficacy and significant toxicities. A central challenge is identifying ideal T-cell populations that effectively eliminate tumors without causing off-target damage, a distinction not captured by existing biomarkers. We show that co-expression patterns of chemokine receptors (CRs) CXCR3, CCR5, and CXCR6 on CD8+ T cells provide a functional "code" defining subsets with divergent roles in on-target immunity versus off-target inflammation. In mouse and human melanoma, a triple-positive (CXCR3+CCR5+CXCR6+) T-cell subset is essential for tumor control, and its genetic signature correlates with positive clinical response, while a distinct CCR5+CXCR6+ subset drives liver immune-related adverse events (IRAEs). Crucially, this CR code reveals that immunotherapy actively reshapes T-cell trafficking patterns, uncovering profound heterogeneity within conventional populations and distinguishing potent anti-tumor progenitors from cells predisposed to exhaustion or off-target migration. This work establishes CR co-expression as a practical tool, providing a surface marker-based strategy to identify and enrich optimized T cells for adoptive therapies, thereby offering a framework to uncouple efficacy from toxicity. One Sentence SummaryCo-expression of CCR5, CXCR6, and CXCR3 provides a functional code that separates T-cell-mediated anti-tumor efficacy from off-target toxicity, enabling the selection of superior cells for safer and more effective cancer immunotherapies. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/693486v2_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@19b0f44org.highwire.dtl.DTLVardef@1076129org.highwire.dtl.DTLVardef@17c0be6org.highwire.dtl.DTLVardef@f14893_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LI{middle dot} CXCR6, CXCR3 and CCR5 co-expression signature stratifies patient survival in human melanoma C_LIO_LI{middle dot} CD8+ T cells co-expressing CXCR6, CXCR3 and CCR5 are critical effectors with high proliferative, cytotoxic, and activation profile in human and mice melanoma C_LIO_LI{middle dot} CD8+ T cells co-expressing CXCR6, CXCR3 and CCR5 drive anti-tumoral responses during checkpoint blockade in both human and mice C_LI

immunology↗

bioRxiv2025

Spatiotemporal Single-Cell Analysis Reveals T Cell Clonal Dynamics and Phenotypic Plasticity in Human Graft-versus-Host Disease

Allogeneic hematopoietic cell transplantation (alloHCT) is curative for various hematologic diseases but often leads to acute graft-versus-host disease (GVHD), a potentially life-threatening complication. We leverage GVHD as a uniquely tractable disease model to dissect complex T-cell-mediated pathology in 27 alloHCT recipients. We integrate pre-transplant identification of alloreactive T-cells with longitudinal tracking across blood and gut, using mixed lymphocyte reaction-based clonal "fingerprinting", TCR clonotyping, single-cell RNA/TCR sequencing, and spatial transcriptomics. Using DecompTCR, a novel computational tool for longitudinal TCR analysis, we uncover clonal expansion programs linked to GVHD severity and TCR features. Multi-omics profiling of gut biopsies reveals enrichment and clonal expansion of CD8 effector and ZNF683(Hobit) resident memory T-cells, cytolytic remodeling of regulatory and unconventional T-cells, and localization of CD8 effector T-cells near intestinal stem cells in crypt loss regions. This framework defines dynamic immune circuit rewiring and phenotypic plasticity with implications for biomarkers and therapies. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=198 SRC="FIGDIR/small/655962v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@178b77dorg.highwire.dtl.DTLVardef@569226org.highwire.dtl.DTLVardef@1951281org.highwire.dtl.DTLVardef@1f1e046_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIPersistent expansion of diverse alloreactive T cell clones is a hallmark of severe GVHD C_LIO_LIDecompTCR reveals dynamic clonal expansion programs linked to GVHD severity and clinical outcome C_LIO_LICD8+ T cell clones exhibit phenotypic plasticity in vivo across intestinal tissue compartments in GVHD C_LIO_LIHigh-resolution spatial profiling shows CD8+ effector T cells localize near intestinal stem cell niches and drive epithelial injury in GVHD C_LI

systems biology↗

bioRxiv2024

Intratumoral CXCL12 Gradients Contextualize Tumor Cell Invasion, Migration and Immune Suppression in Breast Cancer

Although the CXCL12/CXCR4 pathway has been prior investigated for its prometastatic and immuno- suppressive roles in the tumor microenvironment, evidence on the spatiotemporal regulation of these hallmarks has been lacking. Here, we demonstrate that CXCL12 forms a gradient specifically around cancer cell intravasation doorways, also known as Tumor Microenvironment of Metastasis (TMEM) doorways, thus facilitating the chemotactic translocation of prometastatic tumor cells expressing CXCR4 toward the perivascular TMEM doorways for subsequent entry into peripheral circulation. Fur- thermore, we demonstrate that the CXCL12-rich micro-environment around TMEM doorways may cre- ate immunosuppressive niches, whereby CD8+ T cells, despite being attracted to these regions, often exhibit reduced effector functions, limiting their efficacy. While the CXCL12/CXCR4 pathway can mini- mally influence the overall composition of immune cell populations, it biases the distribution of CD8+ T cells away from TMEM doorways, justifying its prior-established role as immunosuppressive factor for CD8+ T cells. Our research suggests that the complex interactions between CXCL12 and the various tumor and immune cell types contributes not only to the completion of the initial steps of the metastatic cascade, but also offers an immunological "sanctuary" to prometastatic tumor cells homed around TMEM doorways. Overall, our study enhances our current understanding on the mechanisms, via which CXCL12 orchestrates tumor cell behavior and immune dynamics, potentially guiding future thera- peutic strategies to combat breast cancer metastasis and improve anti-tumor immunity.

cancer biology↗

bioRxiv2022

Increased Relative Biological Effectiveness of Orthovoltage X-rays Compared to γ-rays in Preclinical Irradiation

PurposeRadionuclide irradiators (137Cs and 60Co) are commonly used in preclinical studies ranging from cancer therapy to stem cell biology. There are institutional initiatives to replace radionuclide sources with lower-energy X-ray sources amidst concerns of radiological terrorism. As researchers transition, there are questions whether the biological effects of {gamma}-rays may be recapitulated with orthovoltage X-rays, since different energy may cause different biological effects. We, therefore, sought to compare the effects of orthovoltage X-rays and 137Cs {gamma}-rays using mouse models of acute radiation syndrome. Experimental Design137Cs {gamma}-rays were compared with Orthovoltage X-rays, generated at 300 kVp, 10 mA with 1 mm Cu or Thoraeus filtration. We assessed 30-day overall survival following whole-body irradiation and calculated LD50 by logistic regression. Comparing equivalent doses delivered with different average energies ([E]), we assessed bone marrow, spleen, and intestinal histology and flow cytometry. ResultsThe LD50 doses are 6.7 Gy, 7.4 Gy and 8.1 Gy with 1 mm Cu filtered ([E]=120 keV), and Thoraeus filtered X-rays ([E]=160 keV), and 137Cs (E=662 keV), respectively. At constant dose, hematopoietic injury was most severe with 1 mm Cu filtered X-rays with the greatest reduction in bone marrow cellularity, stem and progenitor populations, and intestinal crypts and OLFM4+ intestinal stem cells. Thoraeus filtered X-rays provoked an intermediate phenotype, with 137Cs showing the least damage. ConclusionsOur study reveals a dichotomy between physical dose and biological effect relevant as researchers transition to orthovoltage X-rays. With decreasing energy, there is increasing hematopoietic and intestinal injury, necessitating dose-reduction to achieve comparable biological effects. Statement of Translational RelevanceRadiation is used in translational studies in fields ranging from hematopoiesis and stem cell biology to cancer radiotherapy, with 137Cs and 60Co radionuclide sources serving as the most common irradiators. Due to the threat of radiological terrorism using stolen radionuclides, there are institutional initiatives to replace these sources with orthovoltage X-ray irradiators. Yet, as shown in this study, the biological effects of radiation are highly dependent on radiation energy. Lower energy orthovoltage X-rays are absorbed differently than higher energy radionuclide {gamma}-rays, provoking more severe hematopoietic, immunologic, and gastrointestinal radiation injury. Thus, an identical physical dose delivered with beams of differing energy does not produce the same biologic effect. As researchers transition between these sources, it is critical that we appreciate that radiation doses are not interchangeable between them. Understanding the significance of physical dose delivered using different methods will allow us to contextualize past results with future studies.

pathology↗

bioRxiv2021

Aberrant hippocampal transmission and behavior in mice with a stargazin mutation linked to intellectual disability

Mutations linked to neurodevelopmental disorders, such as intellectual disability (ID), are frequently found in genes that encode for proteins of the excitatory synapse. Transmembrane AMPA receptor regulatory proteins (TARPs) are AMPA receptor auxiliary proteins that regulate crucial aspects of receptor function. Here, we investigate an ID-associated mutant form of the TARP family member stargazin. Molecular dynamics analyses showed that the stargazin V143L variant weakens the overall interface of the AMPAR:stargazin complex and hinders the stability of the complex. Knock-in mice for the V143L stargazin mutation manifest cognitive and social deficits and hippocampal synaptic transmission defects. In the hippocampus of stargazin V143L mice, CA1 neurons show impaired spine maturation in basal dendrites, and synaptic ultrastructural alterations. These data demonstrate a causal role for mutated stargazin in the pathogenesis of ID and highlight its role in the development and function of hippocampal synapses.

neuroscience↗