Biology subjects

Bautista, J. M.

Publications and source records attributed to Bautista, J. M..

4 recordsLinked to original sources

bioRxiv2025

Single-cell multiomics reveals epigenetic rewiring of splenic memory B cells during murine malaria reinfection

Malaria induces slow, gradually acquired, non-sterilizing immunity whose cellular and regulatory underpinnings remain incompletely understood. Here, we combine a sequential Plasmodium yoelii 17XNL infection model in BALB/c mice, in which primary parasitemia resolves spontaneously and confers robust protection upon homologous reinfection, with single-cell RNA and chromatin accessibility profiling to dissect how primary infection and recall reshape splenic immunity, with a focus on B cells. We generate a multiomic atlas of >50,000 splenic mononuclear cells, resolving thirteen major immune lineages and 48 subpopulations, and show that B cells dominate the response and diversify into naive/mature, germinal center, memory, and plasmablast compartments. Trajectory analysis reveals distinct differentiation paths towards germinal center, memory, and mature B cells, and uncovers infection-dependent shifts in transcription factor activity, cis-regulatory element usage, and gene regulatory networks. Reinfection is associated with a shift in memory B-cell composition and transcriptional programs towards extrafollicular-like, IgM- conventional memory B cells together with epigenetic modules linked to rapid antibody production. Together, these data provide a systems-level view of B cell plasticity in experimental malaria and provides a mechanistic framework from a highly protective P. yoelii reinfection model with implications for understanding non-sterilizing immunity in endemic settings.

genomics↗

bioRxiv2025

Metabolic Rigidity as a Mechanical Barrier to Malaria: Flickering Loss in PKLR-Deficient Erythrocytes

Pyruvate kinase (PK) deficiency is a rare hereditary enzymopathy caused by mutations in the PKLR gene, leading to reduced glycolytic ATP production in red blood cells (RBCs) and contributing to chronic hemolytic anemia. Here, we use high-speed flickering spectroscopy and passive microrheology to assess how ATP depletion reshapes the nanomechanical properties of RBC membranes. Compared to healthy controls, PKLR-mutant erythrocytes exhibit marked reductions in ATP-dependent flickering amplitude and membrane fluidity, consistent with impaired metabolic elasticity. Strikingly, when infected with Plasmodium yoelii, these metabolically rigidified cells retain mechanical properties that appear to hinder parasite-induced membrane remodeling. By mapping single-cell viscoelastic landscapes across healthy, mutated, infected and coinfected mouse RBC populations, we uncover a potential biomechanical barrier against malaria imposed by glycolytic insufficiency. These findings highlight a mechanobiological axis of host resistance and position label-free flickering analysis as a powerful tool for diagnosing RBC enzymopathies and probing infection susceptibility at the single-cell level.

biophysics↗

bioRxiv2019

Plasmodium falciparum immunodominant IgG epitopes in subclinical malaria

Incomplete non-sterile immunity to malaria is attained in endemic regions after recurrent infections by a large percentage of the adult population, who carry the malaria parasite asymptomatically. Although blood-stage Plasmodium falciparum rapidly elicits IgG responses, the target antigens of partially protective and non-protective IgG antibodies as well as the basis for the acquisition of these antibodies remain largely unknown. We performed IgG-immunomics to screen for P. falciparum antigens and to identify epitopes associated with exposure and clinical disease. Sera from malaria cases identified five prevalent antigens recognized by all analyzed patients IgGs. For further epitope mapping, peptide microarrays designed to cover their sequences were probed with a set of 38 sera samples from adult individuals of an endemic malaria region in Ghana. Eight 20-mer peptides with the highest affinity and frequency of recognition among the population were subsequently validated with 16 sera from the same region, segregated into patients with positive or negative subclinical detection of P. falciparum. Significant binding specificity for two immunodominant antigenic regions was uncovered within the START-related lipid transfer protein and the protein disulfide isomerase PDI8. These 20-mer peptides challenged with sera samples from children under 5 years old displayed specific IgG binding in those with detectable parasitemia, even at subclinical level. These results suggest that the humoral response against START and PDI8 antigens may be triggered even at submicroscopic parasitemia levels in children and may eventually be used to differentially diagnose subclinical malaria in children.\n\nSignificanceMalaria in Africa is a leading cause of morbidity and mortality. The reservoirs of the malaria parasite are asymptomatic patients who carry it subclinically. Identifying the parasite antigens and its fragments that trigger the most common immunity response by immunoglobulin G that partially protect people can have profound implications for both, development of a malaria vaccine and diagnosis of the subclinical parasite carriers. Antigen discovery and mapping, validated with sera from subclinical carriers, showed that immunoglobulin G responses in children against parasites START and PDI8 may eventually be used to differentially diagnose non-infected from subclinical cases. Furthermore, anti-START and anti-PDI8 endemic immunodominance provides association of these antigens with long-term acquired immunity and immune evasion to malaria.

microbiology↗

bioRxiv2018

Recombinant production of rabbit β-Nerve Growth Factor and its biological effect on rabbit sperm

The neurotrophin {beta}-Nerve Growth Factor ({beta}-NGF) is flourishing as a protein with important roles in the ovulation induction process in induced-ovulation species but data in rabbits are still inconclusive, probably due to the species-specificity effect of the neurotrophin to trigger the ovulation. Moreover, {beta}-NGF seems to have a role in sperm function. To clarify these functionalities we aimed, in the present research: 1) to newly synthesize a functional recombinant {beta}-NGF from rabbit (rr{beta}-NGF), 2) to reveal differences in the amino acid sequence of rabbit {beta}-NGF compared to other sequences of induced and spontaneous ovulator species, and 3) to assess the effects of rr{beta}-NGF on sperm viability and motility. The nucleotide sequence of NGF from rabbit prostate was sequenced by Rapid Amplification of cDNA Ends (RACE) and annotated in GenBank (KX528686). Then, rr{beta}-NGF was produced in CHO cells and purified by affinity chromatography. Western blot and MALDI-TOF analyses confirmed the correct identity of the recombinant protein. rr{beta}-NGF functionality was validated in PC12 cells through a successful dose-response effect along 8 days. The comparison of the amino acid sequences of NGF between rabbit and other species suggested some relevant substitutions at its binding site to both the high-(TrkA) and the low-(p75) affinity receptors. The addition of rr{beta}-NGF in rabbit sperm, in a time- and dose-response study, did not affect its viability but slightly changed some of its motility parameters at the highest concentration used (100 ng/ml). Thus, it can be considered that this new recombinant protein may be used for biotechnological and reproduction assisted techniques in ovulation-induced species.

molecular biology↗