Biology subjects

Garcia, J. P.

Publications and source records attributed to Garcia, J. P..

3 recordsLinked to original sources

bioRxiv2024

Immunotherapy with nebulized pattern recognition receptor agonists restores severe immune paralysis and improves outcomes in mice with influenza-associated pulmonary aspergillosis

Influenza-associated pulmonary aspergillosis (IAPA) is a potentially deadly super-infection in patients with influenza pneumonia, especially those with severe disease, underlying immunosuppression, corticosteroid therapy, or requiring intensive care support. Given the high mortality of IAPA, adjunct immunomodulatory strategies remain a critical unmet need. Previously, desensitization of pattern recognition pathways has been described as a hallmark of IAPA pathogenesis and predictor of mortality in IAPA patients. Therefore, we studied the impact of nebulized Toll-like receptor 2/6/9 agonists Pam2 CSK4 (Pam2) and CpG oligodeoxynucleotides (ODN) on infection outcomes and pulmonary immunopathology in a corticosteroid-immunosuppressed murine IAPA model. Mice with IAPA receiving mock therapy showed rapidly progressing disease and a paralyzed immune response to secondary A. fumigatus infection. Nebulized Pam2ODN was well tolerated and significantly prolonged event-free survival. Specifically, dual-dose Pam2ODN therapy before and after A. fumigatus infection led to 81% survival and full recovery of all survivors. Additionally, transcriptional analysis of lung tissue homogenates revealed induction of PRR signaling and several key effector cytokine pathways after Pam2ODN therapy. Moreover, transcriptional and flow cytometric analyses suggested enhanced recruitment of macrophages, natural killer cells, and T cells in Pam2ODN-treated mice. Collectively, immunomodulatory treatment with nebulized Pam2ODN strongly improved morbidity and mortality outcomes and alleviated paralyzed antifungal immunity in an otherwise lethal IAPA model. These findings suggest that Pam2ODN might be a promising candidate for locally delivered immunomodulatory therapy to improve outcomes of virus-associated mold infections such as IAPA.

immunology↗

bioRxiv2024

Glutamate uptake is transiently compromised in the perilesional cortex following controlled cortical impact

Glutamate, the primary excitatory neurotransmitter in the CNS, is regulated by the excitatory amino acid transporters (EAATs) GLT-1 and GLAST. Following traumatic brain injury (TBI), extracellular glutamate levels increase, contributing to excitotoxicity, circuit dysfunction, and morbidity. Increased neuronal glutamate release and compromised astrocyte-mediated uptake contribute to elevated glutamate, but the mechanistic and spatiotemporal underpinnings of these changes are not well established. Using the controlled cortical impact (CCI) model of TBI and iGluSnFR glutamate imaging, we quantified extracellular glutamate dynamics after injury. Three days post-injury, glutamate release was increased, and glutamate uptake and GLT-1 expression were reduced. 7- and 14-days post-injury, glutamate dynamics were comparable between sham and CCI animals. Changes in peak glutamate response were unique to specific cortical layers and proximity to injury. This was likely driven by increases in glutamate release, which was spatially heterogenous, rather than reduced uptake, which was spatially uniform. The astrocyte K+ channel, Kir4.1, regulates activity-dependent slowing of glutamate uptake. Surprisingly, Kir4.1 was unchanged after CCI and accordingly, activity-dependent slowing of glutamate uptake was unaltered. This dynamic glutamate dysregulation after TBI underscores a brief period in which disrupted glutamate uptake may contribute to dysfunction and highlights a potential therapeutic window to restore glutamate homeostasis.

neuroscience↗

bioRxiv2020

CYCA3;4 Is a Post-Prophase Target of the APC/CCCS52A2 E3 Ligase Controlling Formative Cell Divisions in Arabidopsis

The Anaphase Promoting Complex/Cyclosome (APC/C) controls unidirectional progression through the cell cycle by marking key cell cycle proteins for proteasomal turnover. Its activity is temporally regulated by the docking of different activating subunits, known in plants as CDC20 and CCS52. Despite the importance of the APC/C during cell proliferation, the number of identified targets in the plant cell cycle is limited. Here, we used the growth and meristem phenotypes of Arabidopsis CCS52A2-deficient plants in a suppressor mutagenesis screen to identify APC/CCCS52A2 substrates or regulators, resulting in the identification of a mutant cyclin CYCA3;4 allele. CYCA3;4 deficiency partially rescues the early ccs52a2-1 phenotypes, whereas increased CYCA3;4 levels enhances them. Furthermore, whereas CYCA3;4 proteins are promptly broken down after prophase in wild-type plants, they remain present in later stages of mitosis in ccs52a2-1 mutant plants, marking them as APC/CCCS52A2 substrates. Strikingly, CYCA3;4 overexpression results in aberrant root meristem and stomatal divisions, mimicking phenotypes of plants with reduced RBR1 activity. Correspondingly, RBR1 hyperphosphorylation was observed in CYCA3;4-overproducing plants. Our data thus demonstrate that an inability to timely destroy CYCA3;4 attributes to disorganized formative divisions, likely in part caused by the inactivation of RBR1. ONE-SENTENCE SUMMARYTimely post-prophase breakdown of the Arabidopsis cyclin CYCA3;4 by the Anaphase Promoting Complex/Cyclosome is essential for meristem organization and development.

plant biology↗