Biology subjects

Jacinto, A.

Publications and source records attributed to Jacinto, A..

At least 19 recordsLinked to original sources

bioRxiv2026

To Recover or Not to Recover: A Urinary Proteomic Perspective on Severe Acute Kidney Injury

Rationale & Objective Early prediction of renal non-recovery after acute kidney injury (AKI) could support risk-adapted follow-up and clinical decision-making. We evaluated whether a urinary fatty acid-binding protein 3 (FABP3)/apolipoprotein A-I (APOA1) ratio based on Total Protein Approach (TPA) quantification could discriminate renal recovery from non-recovery after severe AKI. Study Design Exploratory biomarker discovery study with outcome-blinded independent validation. Setting & Participants Critically ill adults with KDIGO stage 2 or 3 AKI. Urine was collected 48 hours after AKI diagnosis. The discovery cohort included 20 patients (10 recovered and 10 non-recovered), and the outcome-blinded validation cohort included 10 patients. New Predictor Urinary TPA-derived FABP3/APOA1 ratio (AKI^TPA index). Outcome Renal recovery at day 14, defined as survival with serum creatinine returning to within 0.3 mg/dL or 150% of baseline; patients not meeting these criteria were classified as having non-recovery. Analytical Approach Urinary proteins were analyzed by LC-MS/MS and quantified using TPA. Differential analysis identified FABP3 and APOA1 as oppositely associated with renal outcome. A predefined FABP3/APOA1 threshold of 1 classified patients as non-recovery-like (>1) or recovery-like (<1) and was subsequently applied to the outcome-blinded validation cohort. Results In the discovery cohort, the AKI^TPA index correctly classified 17 of 20 patients (accuracy, 85.0%; sensitivity, 80.0%; specificity, 90.0%; ROC AUC, 0.930). In the validation cohort, 9 patients were evaluable, of whom 7 were correctly classified (accuracy, 77.8%; sensitivity, 75.0%; specificity, 80.0%; ROC AUC, 0.950). Limitations The exploratory design and limited cohort size warrant further validation in larger, independent populations. Conclusions The urinary FABP3/APOA1 TPA ratio showed encouraging preliminary discrimination of renal recovery after severe AKI and warrants prospective clinical validation in larger, independent multicenter cohorts.

biochemistry↗

bioRxiv2026

CCR4+low-density neutrophils define a novel immunosuppressive subset associated with breast cancer progression and early mortality

Neutrophils are increasingly recognized as key players in cancer progression, yet their functional heterogeneity limits their therapeutic exploitation. In breast cancer (BC), elevated circulating and tumor-associated neutrophils have been associated with poor prognosis, and low-density neutrophils (LDN), particularly, have been linked to immunosuppression. However, the specific neutrophil subsets driving these effects remain undefined. Here, we identify a previously unrecognized CCR4-expressing neutrophil subset, strongly enriched among LDN, whose frequency rises with disease stage and correlates with faster progression and shorter survival. Serial blood sampling further showed that CCR4+LDN levels fluctuate in line with clinical course, with increases indicating near-term risk in metastatic patients. Our findings also reveal that this subset has an immunosuppressive signature more pronounced than that of the remaining LDN, migrates preferentially toward tumor-derived chemokines, and dampens T cell-driven tumor killing even when PD-1 is blocked. Additionally, in a pilot cohort of Triple-Negative BC patients on anti-PD-1 therapy, early changes in this population were associated with treatment outcome. Together, these results reveal a distinct neutrophil population that actively contributes to immune escape and tumor progression, establishing CCR4+LDN as a minimally invasive real-time biomarker of disease course and treatment response, and as a promising target for neutrophil-directed therapies in BC.

immunology↗

bioRxiv2026

A role for HDAC3 in regulating histone lactylation and maintaining oocyte chromatin architecture and fertility

The establishment of specialized chromatin architecture is critical for oocyte development, meiotic fidelity, and embryogenesis. Histone lysine lactylation (Kla) has recently emerged as a widespread chromatin modification, yet its developmental dynamics and function in the germ line remain unclear. Here, we define the temporal profile of Kla during Drosophila oogenesis and identified enzymes that regulate its levels. Kla is absent in early germarial stages, becomes highly enriched during prophase I as meiotic chromosomes condense into the karyosome, and decreases when the karyosome decompacts during transcriptional reactivation. Germline depletion of HDAC3 and Nej/p300 reduces Kla in stage-10 oocytes, revealing conserved chromatin-modifying enzymes that maintain lactylation. Among these, HDAC3 is essential for sustaining karyosome architecture, assembling a normal meiotic spindle, and supporting fertility. These findings identify histone lactylation as a dynamic chromatin feature of oogenesis and suggest that Kla contributes to the establishment of meiotic chromatin states required for oocyte competence. SUMMARY STATEMENTHistone lactylation is developmentally regulated during Drosophila oogenesis. HDAC3 maintains histone lactylation and is essential for meiotic chromatin architecture, meiotic progression, and female fertility.

developmental biology↗

bioRxiv2025

Sex-specific control of locomotor behavior by neuronal Arhgef10 in aged Drosophila

Mutations and polymorphisms in the Rho guanine nucleotide exchange factor 10 (ARHGEF10) locus are associated with behavioral and locomotor dysfunctions in humans, including psychiatric disorders and polyneuropathies that show age- and sex-specific prevalence. ARHGEF10 encodes a conserved guanine exchange factor that activates Rho GTPases and has proposed roles in cell migration and adhesion, but the relevant cell types and mechanisms underlying its age- and sex-dependent effects remain unclear. Drosophila darhgef10 gene is the single orthologue of vertebrate ARHGEF10 and its paralogue ARHGEF10L. Here, to gain more direct insight into possible age- and sex-dependent ARHGEF10 neuromuscular functions, we generated darhgef10 knock-out flies and quantified induced walking kinematics with high-speed imaging and coarse spontaneous behaviors--walking, micromovements, rest, and sleep--in open arenas. Mutants of both sexes exhibited abnormal walking kinematics, which worsened with age in females. Cell-type-specific knockdowns indicated that locomotor phenotypes arose primarily from neuronal, rather than glial or muscle, requirements. dArhgef10 was especially critical in glutamatergic motor neurons of aged females. dArhgef10 was also required for wakefulness and activity initiation in females but, surprisingly, not in males. Genetic rescue and isoform expression analyses suggested that sexually-dimorphic expression of long isoforms RC and/or RD underlies at least part of the sex-specific requirements of dArhgef10 in locomotor behavior control, revealing unanticipated complexity in its activity regulation. Collectively, our results suggest ARHGEF10 plays an ancient, conserved role in neurons that promotes proper wakefulness and locomotor activity in an age- and sex-dependent manner.

animal behavior and cognition↗

bioRxiv2025

Neutrophils matter: New clinical insights on their role in the progression of metastatic breast cancer

BackgroundMetastatic breast cancer (BC) remains a significant clinical challenge, needing innovative strategies to improve disease management and extend patient survival. Increased neutrophil levels have been observed in both peripheral blood and tumor tissues of patients with different types of cancer, often being associated with poor clinical outcomes. These findings suggest a crucial role for neutrophils in tumor progression, raising interest in neutrophil-based therapies. However, the functional and phenotypic heterogeneity of neutrophils complicates their therapeutic targeting. This study aims to investigate the clinical impact of immunosuppressive, protumor low-density neutrophils (LDN) in metastatic BC, comparing them with normal high-density neutrophils (HDN) to better understand their role in disease progression. MethodsLDN and HDN subpopulations were isolated from the blood of 151 BC patients (72 metastatic, 79 non-metastatic) using density gradient centrifugation. Their frequency, phenotype, and function were analyzed by flow cytometry and in vitro experiments. Correlations between LDN levels and clinical data from metastatic BC patients were evaluated, alongside individual longitudinal assessments. ResultsLDN accumulated significantly in the blood of BC patients, particularly in those with metastatic disease. Elevated LDN levels in these patients were associated with faster disease progression and reduced life expectancy, regardless of metastatic site. Longitudinal analysis revealed that higher LDN percentages often correlated with adverse clinical events, whereas lower levels of LDN were linked to stable disease. Functionally, LDN exhibited protumor properties, including elevated expressions of PD-L1 and MMP-9, contributing to immunosuppression and metastasis. Unlike HDN, which demonstrated cytotoxicity against tumor cells, LDN failed to reduce BC cell line viability in 3D co-cultures. Notably, BC cell lines exposed to LDN-conditioned medium showed increased invasive capacity and proliferation, while T cells cultured in the same medium displayed impaired activation, likely due to the effect of arginase. ConclusionOur results highlighted LDN and their secreted factors as major drivers of BC progression and increased aggressiveness. These findings suggest that incorporating LDN assessment into clinical practice could aid in identifying high-risk patients and enable more personalized treatment approaches. Furthermore, our data strengthen the relevance of targeting specific neutrophil subsets or their functions to improve metastatic BC management and patient outcomes.

immunology↗

bioRxiv2024

Metabolic reprogramming regulates histone lactylation during zebrafish caudal fin regeneration

Tissue regeneration relies on precise molecular mechanisms controlling cell fate transitions, with cell metabolism emerging as a key regulator. Lactate-derived histone lactylation has recently been identified as an important epigenetic modification involved in the regulation of gene expression across various biological processes. In this study, we report an increase in global histone lactylation and H3K18Lac levels in the mesenchyme and osteoblasts of the zebrafish caudal fin, during the early stages of regeneration. Our findings demonstrate that this epigenetic modification is functionally regulated by increased lactate levels, while inhibition of glycolysis and lactate production significantly reduces histone lactylation. These results suggest that metabolic reprogramming, in response to caudal fin injury, regulates histone lactylation, potentially modulating gene expression essential for cell plasticity and proliferation. This study expands our understanding of how metabolic-epigenetic interactions influence regenerative processes, providing valuable insights for the development of novel therapeutic strategies to enhance tissue repair. Summary statementLactate-derived histone lactylation plays a role in the early stages of zebrafish caudal fin regeneration, coupling metabolic adaptation with tissue repair mechanisms, through epigenetic regulation.

developmental biology↗

bioRxiv2024

Enhancing HLA-DR in Cytotoxic T Lymphocytes is crucial for the development of efficient adoptive T cell Therapies for Breast Cancer

BackgroundDespite advances in breast cancer (BC) therapies, more effective interventions are needed, especially for chemotherapy-resistant tumors. Immune checkpoint inhibitors show promise for triple-negative breast cancer, but their effectiveness across all BC subtypes remains challenging. Therefore, novel strategies, including adoptive cellular therapy, employing patients own T lymphocytes expanded ex vivo, are under investigation. Previously, we demonstrated that cytotoxic T lymphocytes (CTLs) expressing high HLA-DR levels in the tumor microenvironment are associated with a good response to neoadjuvant chemotherapy (NACT), due to their pronounced anti-tumor properties compared to CTLs with low or no HLA-DR expression. In this paper, we demonstrated that HLA-DR expression in CTLs is crucial for efficient T lymphocytes-based therapies. MethodsTo clarify the role of HLA-DR in CTLs anti-tumor abilities, we performed in vitro and in vivo experiments. We also improved a protocol to expand ex vivo HLA-DR-expressing CTLs and employed a 3D co-culture platform to test the potential of different immune agents, namely an anti-PD1, anti-OX40, anti-VEGF and anti-CD137, on CTLs cytotoxicity against BC cells. Additionally, we conducted a bioinformatic analysis of scRNA-seq data of BC patients to better understand the modulation of HLA-DR expression in CTLs. ResultsOur findings revealed that CTLs require HLA-DR expression to eliminate tumor cells. Additionally, we unveiled that blocking HLA-DR or depleting CD4+ T cells compromised CTLs activation and cytotoxicity, suggesting antigen presentation by CTLs through HLA-DR, and CD4+ T cells, as probable mechanisms for CTLs increased anti-tumor immune response and treatment efficacy. We refined an ex vivo stimulation and cytokine supplementation protocol, observing that short-term stimulation increases HLA-DR expression while boosting CTLs functionality, unlike prolonged expansion. This result highlights the importance of prioritizing cell quality, over quantity, for therapy efficiency. Additionally, we verified that anti-PD-1 further increases HLA-DR levels in CTLs, enhancing their anti-tumor efficiency. Notably, an in silico analysis revealed that PD-1 in CTLs shares 34 co-expressed genes with HLA-DR, including several non-coding RNAs, suggesting a PD-1-mediated regulation of HLA-DR expression. ConclusionsGlobally, our findings underscore that heightening HLA-DR expression in CTLs, by combining anti-PD-1 with short-term stimulation, offers promise for improving T lymphocyte-based therapies for BC. Key MessageO_LIWhat is already known on this topic: While immunotherapy holds promise for breast cancer (BC), its success is still limited. Novel strategies are under investigation to improve outcomes across all BC subtypes. Previously we established a correlation between HLA-DR expression on CTLs and a positive response to neoadjuvant chemotherapy, likely due to enhanced anti-tumor properties of HLA-DR-expressing CTLs. However, the specific role of HLA-DR on CTLs and its implications for T lymphocyte-based therapies requires further investigation. C_LIO_LIWhat this study adds: This study revealed that HLA-DR expression is essential for CTLs to effectively eliminate tumor cells. Blocking HLA-DR or depleting CD4+ T cells impairs CTLs activation and cytotoxicity, indicating that HLA-DR-mediated antigen presentation and interaction with CD4+ T cell are crucial for CTLs function. The study also shows that combining ex vivo short-term stimulation and anti-PD-1 treatment increases HLA-DR levels in CTLs, enhancing their anti-tumor activity. C_LIO_LIHow this study might affect research, practice or policy: By emphasizing the importance of optimizing CTLs quality over quantity, this approach has the potential to improve the design of more efficient T lymphocyte-based therapies for BC. This could influence future research directions, clinical practices, and treatment policies, leading to improved therapeutic outcomes. C_LI

immunology↗

bioRxiv2024

Dachsous is a key player in epithelial wound closure by modulating cell shape changes and cytoskeleton dynamics

Epithelia are vital tissues in multicellular organisms, acting as barriers between external and internal environments. Simple epithelia, such as those in embryos and the adult gut, have the remarkable ability to repair wounds efficiently, making them ideal for studying epithelial repair mechanisms. In these tissues, wound closure involves the coordinated action of a contractile actomyosin cable at the wound edge and collective cell movements around the wound. However, the dynamics of cell-cell interactions during this process remain poorly understood. Here, we demonstrate that Dachsous (Ds), an atypical cadherin associated with Planar Cell Polarity, is crucial for efficient epithelial repair in the Drosophila embryonic epidermis. We show that the absence of Ds leads to delayed wound closure, impaired actomyosin cable formation, and altered cell shape changes. Additionally, we reveal that Occluding Junctions are necessary for the proper apical localization of Ds, suggesting an unanticipated interaction between these two molecular complexes. This study identifies Ds as a novel player in epithelial repair and highlights the need for further investigating the molecular mechanisms by which Ds modulates cell shape and tissue morphogenesis. Summary statementThis study shows that the atypical cadherin Dachsous is essential for epithelial wound closure, influencing cytoskeletal dynamics and cell morphology, with Occluding Junctions regulating its subcellular localization.

cell biology↗

bioRxiv2023

Cholesteryl hemiazelate Identified in Cardiovascular Disease Patients Causes in vitro and in vivo Inflammation

Oxidation of polyunsaturated fatty acids (PUFA) in low-density lipoproteins (LDL) trapped in the arterial intima plays a critical role in atherosclerosis. Though there have been many studies on the atherogenicity of oxidized derivatives of unsaturated fatty acid esters of cholesterol, the effects of the oxidation end-products of these esters has been ignored in the literature. Through lipidomics analyses of the plasma of cardiovascular disease patients and human endarterectomy specimens we identified and quantified cholesteryl hemiesters (ChE), end-products of oxidation of polyunsaturated-fatty acid esters of cholesterol. Cholesteryl hemiazelate (ChA) was the most prevalent ChE identified. Importantly human monocytes, monocyte-derived macrophages (MDM) and neutrophils exhibit inflammatory features when exposed to sub-toxic concentrations of ChA in vitro. ChA increases the secretion of proinflammatory cytokines such as IL-1{beta} and IL-6 and modulates the surface markers profile of monocytes and MDM. In vivo, when zebrafish larvae were fed with a ChA-enriched diet they exhibited neutrophil and macrophage accumulation in the vasculature in a caspase 1- and cathepsin B-dependent manner. ChA also triggered lipid accumulation at the bifurcation sites of the vasculature of the zebrafish larvae and negatively impacted their life expectancy. We conclude that ChA has pro-atherogenic properties and can be considered part of a damage-associated molecular pattern (DAMP) in the development of atherosclerosis.

pathology↗

bioRxiv2022

Fin ray branching is defined by TRAP+ osteolytic tubules

The shaping of bone structures relies on various cell types and signalling pathways. Here, we use the zebrafish bifurcating fin rays during regeneration to investigate bone patterning. We found that the regenerating fin rays form via two mineralization fronts that undergo an osteoblast-dependent fusion/stitching until the branchpoint, and that bifurcation is not simply the splitting of one unit into two. We identified tartrate-resistant acid phosphatase-positive (TRAP+) osteolytic tubular structures at the branchpoints, here named osteolytic tubules (OLTs). Chemical inhibition of their bone-resorbing activity strongly impairs ray bifurcation, indicating that OLTs counteract the stitching process. Finally, by testing different osteoactive compounds, we show that the position of the branchpoint depends on the balance between bone mineralization and resorption activities. Overall, these findings provide a new perspective on fin ray formation and bifurcation, and reveal a key role for OLTs in defining the proximo-distal position of the branchpoint. Graphical summary O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=98 SRC="FIGDIR/small/491182v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@7d0b9dorg.highwire.dtl.DTLVardef@1859078org.highwire.dtl.DTLVardef@1cfb816org.highwire.dtl.DTLVardef@3ec7f3_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗

bioRxiv2022

Zebrafish caudal fin amputation induces a metabolic switch necessary for cell identity transitions and cell cycle re-entry to support blastema formation and bone regeneration

Regeneration depends on the ability of mature cells at the injury site to respond to injury, generating tissue-specific progenitors that incorporate the blastema and proliferate to reconstitute the original organ architecture. The metabolic microenvironment has been tightly connected to cell function and identity during development and tumorigenesis. Yet, the link between metabolism and cell identity at the mechanistic level in a regenerative context remains unclear. The adult zebrafish caudal fin, and bone cells specifically, have been crucial for the understanding of mature cell contribution to tissue regeneration. Here, we use this model to explore the relevance of glucose metabolism for the cell fate transitions preceding new osteoblast formation and blastema assembly. We show that injury triggers a shift in the metabolic profile at early stages of regeneration, enhancing glycolysis at the expense of mitochondrial oxidation. This metabolic switch mediates transcriptional changes that make mature osteoblast amenable to be reprogramed into pre-osteoblasts and induces cell cycle re-entry and progression. Manipulation of the metabolic profile led to severe reduction of the pre-osteoblast pool, diminishing their capacity to generate new osteoblasts, and to a complete abrogation of blastema formation. Overall, our data indicate that metabolic alterations have a powerful instructive role in regulating genetic programs that dictate fate decisions and stimulate proliferation, thereby providing a deeper understanding on the mechanisms regulating blastema formation and bone regeneration.

developmental biology↗

bioRxiv2021

Determination of HLA-DR level in cytotoxic T lymphocytes: a new validated tool to predict breast cancer response to treatment

BackgroundNeoadjuvant chemotherapy (NACT) is the usual treatment for locally-advanced breast cancer (BC). However, more than half of the patients lack an effective response to this treatment. Thus, its urgent to find predictive biomarkers. Recently, we proposed the HLA-DR expression level in cytotoxic T lymphocytes (CTLs) as a robust biomarker to select, in advance, patients that will actually benefit from NACT. Patients and MethodsA total of 202 BC patients, 102 of which submitted to NACT, were enrolled in this study. 61 biopsies and 41 blood samples collected pre-NACT and 100 non-NACT tumor samples were immunophenotyped by flow cytometry. Both NACT and non-NACT patients were followed up for 34 months. Blood-isolated immune cells were cultured with BC cell lines in a 3D system. ResultsHere we confirmed that HLA-DR level in CTLs is a highly sensitive and specific biomarker to predict BC response to NACT, reflected in circulation and independent of the patients age, BC subtype and other tumor-immunological features. Therefore, we developed a predictive probability model, based on the determination of HLA-DR level in tumor-infiltrating CTLs, that could be used to guide therapeutic decisions. Interestingly, this biomarker was also associated with progression-free survival, regardless the treatment. Contrary to HLA-DRnegative CTLs, HLA-DR+ CTLs were able to reduce the viability of tumor cells, in culture, in agreement with their higher expression of activation, proliferation and cytotoxicity-related molecules. Tissue-residency and memory markers were also increased in HLA-DR+ CTLs. These anti-tumor features of HLA-DR+ CTLs may justify the clinical observations. ConclusionHLA-DR level in CTLs is a validated and independent biomarker to predict response to NACT which allow the establishment of a clinical meaningful tool to select in advance patients that will truly benefit from this treatment. Intriguingly, it may be further used as a biomarker of BC patients general prognosis. Highlights- HLA-DR level in cytotoxic T cells is an independent predictive factor of breast cancer response to NACT - A predictive probability model based on this biomarker was developed as a new tool to improve treatment decisions - HLA-DR level in cytotoxic T cells is also reflected systemically - HLA-DR level in cytotoxic T cells is also a prognostic factor, associated with progression-free survival - HLA-DR+ cytotoxic T cells exhibit several phenotypic and functional anti-tumor characteristics

immunology↗

bioRxiv2021

Circulating Low Density Neutrophils of Breast Cancer Patients are Associated with their Worse Prognosis due to the Impairment of T cell Responses

Neutrophils are prominent immune components of solid tumors, which can protect against the onset of cancer (N1) or have pro-tumor activity (N2). Circulating neutrophils, divided into high density neutrophils (HDN) and low density neutrophils (LDN), functionally mirror those N1 and N2 cells, respectively. LDN, a rare subset in non-pathological conditions, have been extensively studied in cancer, due to their frequency in this disease and their pro-tumor phenotype. However, this has been mainly demonstrated in animal models and proper validation in humans is an urgent need. Here, we further enlighten the clinical impact of LDN in a cohort of breast cancer (BC) patients. We observed that LDN were practically absent in healthy donors blood, while were significantly increased in the blood of BC patients, particularly with metastatic disease. Relevant for a clinical translation, within the population of non-metastatic patients, LDN were more prevalent in patients with poor response to neoadjuvant chemotherapy than in responders. The association of a higher incidence of circulating LDN and the worse prognosis of BC patients could be explained by the pro-tumor/immunosuppressive characteristics exhibited by these cells. Namely, there are more LDN expressing the immunosuppressive marker PD-L1, than HDN. Additionally, LDN also showed increased expression of activation markers; a robust formation of neutrophil extracellular traps; an augmented phagocytic activity; and a higher capacity to release reactive oxygen species, which may contribute for tumor development and metastization. Moreover, the percentage of LDN in BC patients blood was negatively correlated with activated cytotoxic T lymphocytes and positively correlated with the immunosuppressive CCR4+ regulatory T cells, corroborating their impairment on the anti-tumor immune responses, which was further demonstrated ex vivo. Hence, this study reveals the potential of LDN as a clinical meaningful biomarker of BC response to treatment and opens new avenues for developing targeted immunotherapies.

immunology↗

bioRxiv2020

Differential expression between African-ancestry and White patients diagnosed with Triple-Negative Breast Cancer: EGFR, Myc, Bcl2 and β-Catenin as ancestry-associated markers

PurposeTriple-negative breast cancer (TNBC) has a higher incidence, a younger age of onset, and a more aggressive behavior in African-ancestry women. Biological disparities have been suggested as an important factor influencing the ancestry-associated TNBC discrepancy. In this study, we sought to identify ancestry-associated differential gene and protein expression between African-ancestry and White TNBC patients, controlling for patients menopause status and pathological staging at diagnosis. MethodsDifferential gene expression analyses (DGEA) were performed using RNA-sequencing data from The Cancer Genome Atlas (TCGA). Gene set enrichment analysis (GSEA) and Ingenuity Pathway Analysis (IPA), with focus on network design, were performed to highlight candidate genes for further validation through immunohistochemistry of TNBC samples from patients followed in Portugal. ResultsWith 52 African-American and 90 White TNBC patients included, TCGAs data corroborate that African-American patients have a higher TNBC incidence (28.42% vs 11.89%, p<0.0001). Particularly, premenopausal and stage II disease African-American patients also have significantly lower survival probability, comparing with White patients (log-rank p=0.019 and 0.0038, respectively). DGEA results suggest that expression profile differences are more associated with TNBC staging than with patients menopause status. Hippo pathway and cellular community gene sets are downregulated, while breast cancer gene set is upregulated in African-Americans, comparing with White TNBC patients. Furthermore, MAPK pathway gene set is upregulated when controlling for stage II disease. Due to their central role in highly scored networks resulted from IPAs network design, EGFR, Myc and Bcl2 genes were selected for further validation through immunohistochemistry. We also included {beta}-Catenin in the validation study as it is consensually reported to be required in TNBC tumorigenesis. Although patients used in the DGEA and in the immunohistochemistry experiments are geographically and culturally distinct, both groups of African-ancestry patients are mostly of western-African ancestry and, interesting, differential gene and protein expression matched. ConclusionsWe found ancestry-associated gene expression patterns between African-ancestry and White TNBCs, particularly when controlling for menopause status or staging. EGFR, Myc, Bcl2 and {beta}-catenin gene and protein differential expression matching results in distinct populations suggest these markers as being important indicators of TNBCs ancestry-associated development.

cancer biology↗

bioRxiv2020

Depletion of senescent cells improves functional recovery after spinal cord injury

Persistent senescent cells (SCs) are known to underlie ageing-related chronic disorders, but it is now recognized that SCs may be at the center of tissue remodeling events, namely during development or organ repair. Here we show that two distinct senescence profiles are induced in the context of a spinal cord injury between the regenerating zebrafish and the non-regenerating mouse. While induced-SCs in the zebrafish are progressively cleared out, they accumulate over time in mice. Depletion of SCs in spinal cord injured mice, with different senolytic drugs, improved locomotor, sensory and bladder functions. This functional recovery is associated with improved myelin sparing, reduced fibrotic scar, attenuated inflammation and increased axonal growth. Targeting SCs is a promising therapeutic strategy not only for spinal cord injuries but potentially for other organs that lack regenerative competence.

neuroscience↗

bioRxiv2019

Drp1-mediated mitochondrial fission regulates calcium and F-actin dynamics during wound healing

Mitochondria adapt to cellular needs by changes in morphology through fusion and fission events, referred to as mitochondrial dynamics. Mitochondrial function and morphology are intimately connected and the dysregulation of mitochondrial dynamics is linked to several human diseases. In this work, we investigated the role of mitochondrial dynamics in wound healing in the Drosophila embryonic epidermis. Mutants for mitochondrial fusion and fission proteins fail to close their wounds, indicating that the regulation of mitochondrial dynamics is required for wound healing. By live-imaging, we found that loss of function of the mitochondrial fission protein Dynamin-related protein 1 (Drp1) compromises the increase of cytosolic and mitochondrial calcium upon wounding and leads to F-actin defects at the wound edge, culminating in wound healing impairment. Our results highlight a new role for mitochondrial dynamics in the regulation of calcium and F-actin during epithelial repair.\n\nSummaryWe show that mitochondrial dynamics proteins are required for epithelial repair. In particular, Drp1 loss-of-function leads to defects in the dynamics of cytosolic and mitochondrial calcium and F-actin upon wounding.

cell biology↗

bioRxiv2018

The Aryl Hydrocarbon Receptor senses the Henna pigment Lawsone and mediates Yin-Yang effects on skin homeostasis

As a first host barrier, the skin is constantly exposed to environmental insults that perturb its integrity. Tight regulation of skin homeostasis is largely controlled by the aryl hydrocarbon receptor (AhR). Here, we demonstrate that Henna and its major pigment, the naphthoquinone Lawsone activate AhR, both in vitro and in vivo. In human keratinocytes and epidermis equivalents, Lawsone exposure enhances the production of late epidermal proteins, impacts keratinocyte differentiation and proliferation, and regulates skin inflammation. To determine the potential use of Lawsone for therapeutic application, we harnessed human, murine and zebrafish models. In skin regeneration models, Lawsone interferes with physiological tissue regeneration and inhibits wound healing. Conversely, in a human acute dermatitis model, topical application of a Lawsone-containing cream ameliorates skin irritation. Altogether, our study reveals how a widely used natural plant pigment is sensed by the host receptor AhR, and how the physiopathological context determines beneficial and detrimental outcomes.

cell biology↗

bioRxiv2018

Enterococcus faecalis V583 LuxS/AI-2 system is devoid of role in intra-species quorum-sensing but contributes to virulence in a Drosophila host model

The AI-2 i nterspecies quorum-sensing molecule is produced by the LuxS enzyme and has been ascribed a role in virulence in several bacteria. The nosocomial pathogen Enterococcus faecalis inhabits several different environments where multispecies communities are established. However, despite the presence of a luxS gene in this pathogen, its role in E. faecalis pathogenesis has never been assessed. In the present work, we deleted the luxS gene from the vancomycin-resistant clinical isolate E. faecalis V583 and demonstrated the lack of AI-2 production by the mutant strain. Using microarrays and externally added (S)-4,5-dihydroxy-2,3-pentanedione we showed that AI-2 is not sensed by E. faecalis as a canonical quorum-sensing molecule and that the luxS mutation caused pleiotropic effects in gene expression, which could not be complemented by extracellularly added AI-2. These global differences in gene expression affected several gene functional roles, mainly those enrolled in metabolism and transport. Metabolic phenotypi ng of the luxS mutant, using Biolog plates, showed differences in utilization of galactose. AI-2 production by LuxS was shown to be irrelevant for some phenotypes related to the pathogenic potential of E. faecalis namely biofilm formation, adhesion to Caco-2 cells, resistance to oxidative stress and survival inside J-774 macrophages. However, the luxS mutant was attenuated when tested in the Drosophila septic injury model, as its deletion led to delayed fly death. Overall our findings show that differential gene expression related to the luxS mutation cannot be ascribed to quorum-sensing. Moreover, the role of LuxS appears to be limited to metabolism.

microbiology↗