Biology subjects

Santamaria, G.

Publications and source records attributed to Santamaria, G..

7 recordsLinked to original sources

bioRxiv2024

Host-strain compatibility influences transcriptional responses in Mycobacterium tuberculosis infections

Tuberculosis, caused by Mycobacterium tuberculosis, is a leading cause of infectious mortality and affects humans and other mammals. Understanding the drivers of its host-specificity shapes the landscape of infectivity, which could potentially inform strategies for tuberculosis management. We hypothesise that host-strain compatibility influences infection outcome and we aim to reveal bacteria and host specific transcriptional responses during in vitro infections. We infected human and bovine cell lines with two human-associated M. tuberculosis strains from lineages 5 and 6, as well as two animal-associated strains (Mycobacterium bovis and the Chimpanzee bacillus), and quantified infection ratios, cell death, and transcriptional responses. By integrating those data from different compatibility combinations, we identified global transcription profiles associated with strain-host compatibility. Our results show that the most compatible host-strain combinations had higher infection rates, and different transcriptional patterns than low-compatibility infections. Both hosts had similar transcriptional responses to their most compatible strains, upregulating pathways related with increased cell proliferation. Host proliferation could potentially favour bacterial growth, explaining the success of the strain in its corresponding host. Conversely, both hosts responded to non-associated strains with defence related transcriptional patterns, among other pathways, supporting their lower success in the non-associated host. Finally, we revealed bacteria and host-specific expression patterns in molecules implicated in immune response and inflammation through the eicosanoid pathway. In conclusion, we confirmed that bacteria-host compatibility determines common transcriptional responses, but also specific responses that depend on the infecting strain. This study enhances the understanding of host-specific adaptation mechanisms in M. tuberculosis.

microbiology↗

bioRxiv2023

Increased pulmonary monocyte infiltration and attenuated phagocytosis defines perinatal dysfunction of innate immunity in Cystic Fibrosis

In Cystic Fibrosis (CF) patients, cycles of infection and inflammation lead to fatal lung damage. While diminished mucus clearance is restored by highly effective CFTR modulator therapy, inflammation and infection persist in treated patients, suggesting alternative mechanisms may contribute to impaired immunity in CF. Here, we made use of a CF pig model to investigate the innate immune system at birth, before the onset of infection. We observed a substantial change in the composition of tissue resident immune cells towards emergency myelopoiesis, accompanied by increased infiltration of monocytes into CF lungs. A more immature status in the transcriptome profile of classical monocytes in CF pigs and preschool children with CF correlated with reduced phagocytic capacity, confirming a congenital and translationally conserved aberration of the immune system in CF. The lack of CFTR expression in circulating monocytes indicates an indirect etiology of these effects and suggests that additional immunological treatments are necessary for CF patients. One Sentence SummaryIncreased infiltration of lung tissue by monomyeloid cells and their impaired phagocytic potential cause dysfunctional imprinting of mucosal immunity in Cystic Fibrosis airways at birth and suggest early and specific treatment of the innate immune system in patients.

immunology↗

bioRxiv2022

Retinoic acid signaling modulation guides in vitro specification of human heart field-specific progenitor pools

Cardiogenesis relies on the precise spatiotemporal coordination of multiple progenitor populations. Understanding the specification and differentiation of these distinct progenitor pools during human embryonic development is crucial for advancing our knowledge of congenital cardiac malformations and designing new regenerative therapies. By combining genetic labelling, single-cell transcriptomics, and ex vivo human-mouse embryonic chimeras we uncovered that modulation of retinoic acid signaling instructs human pluripotent stem cells to form heart field-specific progenitors with distinct fate potentials. In addition to the classical first and second heart fields, we observed the appearance of juxta-cardiac field progenitors giving rise to both myocardial and epicardial cells. Applying these findings to stem-cell based disease modelling we identified specific transcriptional dysregulation in first and second heart field progenitors derived from stem cells of a patient with hypoplastic left heart syndrome. This highlights the suitability of our in vitro differentiation platform for studying human cardiac development and disease.

cell biology↗

bioRxiv2021

Early Disruption of Photoreceptor Cell Architecture and Loss of Vision in a Humanized Pig Model of Usher Syndrome

Usher syndrome (USH) is the most common form of monogenic deaf-blindness. Loss of vision is untreatable and, so far, there are no suitable animal models for testing therapeutic strategies. By introducing a human mutation into the harmonin-encoding USH1C gene in pigs, we generated the first translational animal model for USH type 1 with characteristic hearing defect, vestibular dysfunction and visual impairment. Changes in photoreceptor architecture, quantitative motion analysis and electroretinography were characteristics of the reduced retinal virtue in USH1C pigs. Primary cells from those animals and USH1C patients showed significantly elongated primary cilia, compared to wild-type, confirming the nature of USH as a true and general ciliopathy and proving the therapeutic capacity of gene supplementation and gene repair approaches.

genetics↗

bioRxiv2021

Sequential defects in cardiac lineage commitment and maturation cause hypoplastic left heart syndrome

BackgroundComplex molecular programs in specific cell lineages govern human heart development. Hypoplastic left heart syndrome (HLHS) is the most common and severe manifestation within the spectrum of left ventricular outflow tract obstruction defects occurring in association with ventricular hypoplasia. The pathogenesis of HLHS is unknown, but hemodynamic disturbances are assumed to play a prominent role. MethodsTo identify perturbations in gene programs controlling ventricular muscle lineage development in HLHS, we performed: i) whole-exome sequencing of 87 HLHS parent-offspring trios, ii) nuclear transcriptomics of cardiomyocytes from ventricles of 4 patients with HLHS and 15 controls at different stages of heart development, iii) single cell RNA sequencing and iv) 3D modeling in iPSCs from 3 patients with HLHS and 3 controls. ResultsGene set enrichment and protein network analyses of damaging de-novo mutations and dysregulated genes from ventricles of patients with HLHS suggested alterations in specific gene programs and cellular processes critical during fetal ventricular cardiogenesis, including cell-cycle and cardiomyocyte maturation. Single-cell and 3D modeling with iPSCs demonstrated intrinsic defects in the cell-cycle/UPR/autophagy hub resulting in disrupted differentiation of early cardiac progenitor lineages leading to defective cardiomyocyte-subtype differentiation/maturation in HLHS. Additionally, premature cell-cycle exit of ventricular cardiomyocytes from HLHS patients prevented normal tissue responses to developmental signals for growth leading to multinucleation/polyploidy, accumulation of DNA damage, and exacerbated apoptosis, all potential drivers of left ventricular hypoplasia in absence of hemodynamic cues. ConclusionsOur results highlight that despite genetic heterogeneity in HLHS, many mutations converge on sequential cellular processes primarily driving cardiac myogenesis, suggesting novel therapeutic approaches.

developmental biology↗

bioRxiv2020

Metabolic homeostasis controls the diversity of cooperative swarming in pathogenic bacteria

Microbes have disproportionate impacts on the macroscopic world. This is in part due to their ability to grow to large groups and cooperatively secrete massive amounts of secondary metabolites that impact their environment. Yet, the conditions enabling secondary metabolism without compromising primary needs remain unclear. Here we investigated the biosynthesis of rhamnolipids, a secondary metabolite that Pseudomonas aeruginosa makes to decrease the surface tension of surrounding liquid. Using a combination of genomics, metabolomics, transcriptomics, and mathematical modeling we show that biosynthesis of rhamnolipids from glycerol varies inconsistently across the phylogenetic tree; instead, non-producer lineages are also those worse at reducing the oxidative stress of primary glycerol metabolism. The link to oxidative stress explains the inconsistent distribution across the P. aeruginosa tree, adding a new layer to the regulation of rhamnolipids--a microbial secondary metabolite important for fitness in natural and clinical settings. SignificanceThe bacterium Pseudomonas aeruginosa is a major source of hospital-acquired infections. This pathogens knack for virulence relies on its ability to multiply and secrete massive amounts of substances that overwhelm microbial competitors and weaken host defenses. It remains unclear how the bacteria conciliate their need to grow and multiply--a need at the individual-level-- with their ability to secrete products--a need of the population. Here we combined genomics, metabolomics and mathematical modeling to study the biosynthesis of rhamnolipids, a surfactant that P. aeruginosa makes to reduce the surface tension of surrounding liquids. Our study reveals a new link between oxidative stress and rhamnolipid synthesis, which helps explain how this important bacterial product has evolved and how it persists in many lineages of pathogens.

systems biology↗

bioRxiv2020

Primate heart regeneration via migration and fibroblast repulsion by human heart progenitors

SUMMARYHuman heart regeneration is one of the most critical unmet clinical needs at a global level1. Muscular regeneration is hampered both by the limited renewing capacity of adult cardiomyocytes2-4 and the onset of cardiac fibrosis5,6, resulting in reduced compliance of the tissue. Primate have proven to be ideal models for pluripotent stem cell strategies for heart regeneration, but unravelling specific approaches to drive cell migration to the site of injury and inhibition of subsequent fibrosis have been elusive. Herein, by combining human cardiac progenitor lineage tracing and single-cell transcriptomics in injured non-human primate heart bio-mimics, we uncover the coordinated muscular regeneration of the primate heart via directed migration of human ventricular progenitors to sites of injury, subsequent fibroblast repulsion targeting fibrosis, and ultimate functional replacement of damaged cardiac muscle by differentiation and electromechanical integration. Single-cell RNAseq captured distinct modes of action, uncovering chemoattraction mediated by CXCL12/CXCR4 signalling and fibroblast repulsion regulated by SLIT2/ROBO1 guidance in organizing cytoskeletal dynamics. Moreover, transplantation of human cardiac progenitors into hypo-immunogenic CAG-LEA29Y transgenic porcine hearts following injury proved their chemotactic response and their ability to generate a remuscularized scar without the risk of arrhythmogenesis in vivo. Our study demonstrates that inherent developmental programs within cardiac progenitors are sequentially activated in the context of disease, allowing the cells to sense and counteract injury. As such, they may represent an ideal bio-therapeutic for functional heart rejuvenation.Competing Interest StatementThe authors have declared no competing interest.View Full Text

cell biology↗