Biology subjects

Rojo, R.

Publications and source records attributed to Rojo, R..

4 recordsLinked to original sources

bioRxiv2026

Integrated serum proteomics and autoantibody analyses reveal a biomarker signature predictive of flare during biologic tapering in rheumatoid arthritis

BackgroundRheumatoid arthritis (RA) is a chronic immune-mediated inflammatory disease characterized by a heterogeneous clinical course with periods of remission and flare. Although biologic DMARDs (bDMARDs) have revolutionized RA treatment by enabling sustained disease control, their long-term use is associated with adverse effects and high costs, making dose tapering an attractive but clinically challenging strategy. The lack of reliable biomarkers to predict flare risk limits safe implementation of treatment de-escalation. This study aimed to identify novel circulating protein biomarkers associated with flare risk in RA patients undergoing bDMARDs tapering, useful to enable biomarker-guided treatment optimization strategies. MethodsA discovery proteomic analysis using mass spectrometry was performed on baseline serum samples from a subset of the OPTIBIO clinical trial (n=44), followed by validation in the full cohort (n=194) using ELISA. Functional pathway analysis explored biological processes associated with candidate biomarkers. In parallel, anti-cytokine autoantibodies were profiled using multiplex immunoassays. Logistic and Cox regression models were used to assess associations with flare risk. Predictive models integrating biomarkers and clinical variables were evaluated using receiver operating characteristic (ROC) analysis, sensitivity and specificity metrics, and decision curve analysis to assess clinical utility. ResultsMass spectrometry identified 806 proteins, of which 87 were differentially expressed at baseline between patients who flared and those who maintained remission during follow-up within the intervention (tapering) arm. Functional enrichment analysis highlighted immune-regulatory and innate immune pathways. Among the candidates, V-set immunoglobulin-domain-containing 4 (VSIG4) was validated as a biomarker associated with increased flare risk. Anti-interferon-{gamma} (anti-IFN{gamma}) autoantibodies were also associated with flare. A combined model including VSIG4, anti-IFN{gamma}, and the clinical variable DAS28-CRP improved predictive performance compared with clinical variables alone (AUC 0.76 vs 0.66), achieving significantly higher sensitivity. Decision curve analysis demonstrated higher net benefit of the combined model, indicating improved clinical decision-making. In a secondary analysis focused on patients with prolonged remission, representing the most suitable candidates for safe treatment tapering, the model performance further improved (AUC 0.84). ConclusionIntegration of novel serum proteomic and autoantibody biomarkers with clinical parameters improves prediction of flare during biologic tapering in RA and provides clinically relevant benefit for patient stratification. These findings support further development of biomarker-driven approaches for personalized treatment optimization strategies.

molecular biology↗

bioRxiv2025

Microglia are not required for normal postnatal brain development and cognitive function in the rat.

The development, maintenance and survival of microglia, the brains resident immune cells, requires signalling via the colony stimulating factor 1 receptor (CSF1R). In mice, the Fms intronic regulatory element (FIRE), a highly conserved super enhancer, is required for CSF1R expression in microglia and germ-line deletion of FIRE leads to microglial deficiency. We have generated Csf1r{Delta}FIRE/{Delta}FIRE (Fireko) rats using CRISPR/Cas9. Fireko rats are born at expected Mendelian frequency, grow normally and survive to adulthood. Like Fireko mice, they lack microglia and subpopulations of resident macrophages in kidney and heart, but retain the other brain associated macrophages and resident populations in the liver, spleen and lungs. In contrast to mutant mice, macrophages in the peritoneum are unaffected and CSF1R expression is not completely abolished in the blood. Aside from the loss of microglia-specific transcripts, the Fireko has no effect on expression of genes associated with neurons, oligodendrocytes or astrocytes in adult rats but is associated with detectable calcification in the thalamus. Despite the absence of microglia, we detected no significant differences in ethologically relevant behaviours compared to littermates. The results suggest that microglia are not essential for normal cognitive development. Fireko rats provide an alternative to mice as a model for human microglial deficiency and the functions of microglia in development and homeostasis in the brain.

immunology↗

bioRxiv2025

Microglia regulate nucleus accumbens synaptic development and circuit function underlying threat avoidance behaviors

While CNS microglia have well-established roles in synapse pruning during neurodevelopment, only a few studies have identified roles for microglia in synapse formation. These studies focused on the cortex and primary sensory circuits during restricted developmental time periods, leaving substantial gaps in our understanding of the early developmental functions of microglia. Here we investigated how the absence of microglia impacts synaptic development in the nucleus accumbens (NAc), a region critical for emotional regulation and motivated behaviors and where dysfunction is implicated in psychiatric disorders that arise early in life. Using a genetically modified mouse that lacks microglia (Csf1r {Delta}FIRE/{Delta}FIRE), we found blunted excitatory synapse formation in the NAc. This effect was most prominent during the second and third postnatal weeks, when we previously found microglia to be overproduced, and was accompanied by an increase in presynaptic release probability and alterations in postsynaptic kinetics. Tissue-level NAc proteomics confirmed that microglial absence impacted numerous proteins involved in synapse structure, trans-synaptic signaling, and pre-synaptic function. However, microglial absence did not perturb levels of astrocyte-derived cues and adhesive proteins that promote synaptogenesis, suggesting that reduced synapse number may be caused by absence of a microglial-derived synaptogenic cue. Although observed electrophysiological synaptic changes were largely normalized by adulthood, we identified lasting effects of microglial absence on threat avoidance behavior, and these behavioral effects were directly associated with alterations of NAc neuronal activity. Together, these results indicate a critical role for microglia in regulating the synaptic landscape of the developing NAc and in establishing functional circuits underlying adult behavioral repertoires.

neuroscience↗

bioRxiv2018

Maternal tamoxifen treatment expands the macrophage population of early mouse embryos.

Several different transgenic tamoxifen-inducible cre reporter lines have been used to analyse the contribution of embryonic precursors to the development of the mononuclear phagocyte system in mice. Here we show that tamoxifen treatment of the mother at 8.5dpc with doses commonly-used in lineage trace studies produces a 4-5-fold expansion of the embryonic leukocyte populations by 10.5dpc, detected in whole mounts of embryos using a Csf1r reporter gene or separately by expression of Csf1r, Itgam (CD11b), Adgre1 (F4/80) or Ptprc (CD45) mRNA. These findings indicate that tamoxifen cannot be considered a neutral agonist in macrophage lineage trace studies.\n\nSummary sentenceTreatment of pregnant mice with tamoxifen in early gestation produces a large expansion of the embryonic macrophage population.

immunology↗