Biology subjects

Altier, C.

Publications and source records attributed to Altier, C..

4 recordsLinked to original sources

bioRxiv2024

Genome-wide screen of Mycobacterium tuberculosis-infected macrophages identified the GID/CTLH complex as a determinant of intracellular bacterial growth.

SummaryThe eukaryotic GID/CTLH complex is a highly conserved E3 ubiquitin ligase involved in a broad range of biological processes. However, a role of this complex in host antimicrobial defenses has not been described. We exploited Mycobacterium tuberculosis (Mtb) induced cytotoxicity in macrophages in a FACS based CRISPR genetic screen to identify host determinants of intracellular Mtb growth restriction. Our screen identified 5 (GID8, YPEL5, WDR26, UBE2H, MAEA) of the 10 predicted members of the GID/CTLH complex as determinants of intracellular growth of both Mtb and Salmonella serovar Typhimurium. We show that the antimicrobial properties of the GID/CTLH complex knockdown macrophages are mediated by enhanced GABAergic signaling, activated AMPK, increased autophagic flux and resistance to cell death. Meanwhile, Mtb isolated from GID/CTLH knockdown macrophages are nutritionally starved and oxidatively stressed. Our study identifies the GID/CTLH complex activity as broadly suppressive of host antimicrobial responses against intracellular bacterial infections. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=122 SRC="FIGDIR/small/592714v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@1fc273aorg.highwire.dtl.DTLVardef@173927borg.highwire.dtl.DTLVardef@95cb02org.highwire.dtl.DTLVardef@42fcea_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2023

Induction of antiviral Interferon-Stimulated Genes (ISGs) by neuronal STING promotes the resolution of pain

Inflammation and pain are intertwined responses to injury, infection, or chronic diseases. While acute inflammation is essential in determining pain resolution and opioid analgesia, maladaptive processes occurring during resolution can lead to the transition to chronic pain. Here we found that inflammation activates the cytosolic DNA-sensing protein Stimulator of Interferon Genes (STING) in DRG nociceptors. Neuronal activation of STING promotes signaling through TANK-binding kinase 1 (TBK1) and triggers an interferon-beta (IFN{beta}) response that mediates pain resolution. Notably, we found that mice expressing a nociceptor-specific gain-of-function mutation in STING exhibited an IFN gene signature that reduced nociceptor excitability and inflammatory hyperalgesia through a KChIP1-Kv4.3 regulation. Our findings reveal a role of IFN-regulated genes (IRGs) and KChIP1 downstream of STING, in the resolution of inflammatory pain.

neuroscience↗

bioRxiv2019

Effects of treatment with enrofloxacin or tulathromycin on fecal microbiota composition and function of dairy calves

The increasing concerns with antimicrobial resistance highlights the need for studies evaluating the impacts of antimicrobial use in livestock on antimicrobial resistance using new sequencing technologies. Through shotgun sequencing, we investigated the changes in the fecal microbiome composition and function, with a focus on functions related to antimicrobial resistance, of dairy calves. Heifers 2 to 3 weeks old, which were not treated with antibiotics by the farm before enrollment, were randomly allocated to one of three study groups: control (no treatment), enrofloxacin, or tulathromycin. Fecal samples were collected at days 4, 14, 56 and 112 days after enrollment, and DNA extraction and sample preparation and sequencing was conducted. The effect of antibiotic treatment on each taxon and functional level by time (including Day 0 as a covariate) revealed few changes in the microbiota. At the genus level, enrofloxacin group had higher abundance of Blautia, Coprococcus and Desulfovibrio and lower abundance of Bacteroides when compared to other treatment groups. The SEED database was used for functional analyses, which showed that calves in the enrofloxacin group started with a higher abundance of \"Resistance to antibiotics and toxic compounds\" function on Day 0, however an increase in antibiotic resistance genes after treatment with enrofloxacin was not observed. \"Resistance to Fluoroquinolones\" and \"Erythromycin resistance\", of relevance given the study groups, were not statistically different in abundance between treatment groups. \"Resistance to fluoroquinolones\" increased during the study period regardless of treatment group. Despite small differences over the first weeks between treatment groups, at Day 112 the microbiota composition and functional profile was similar among all study groups. These findings show that metaphylaxis treatment of dairy calves with either enrofloxacin or tulathromycin have minimal impacts on the microbial composition and functional microbiota of dairy calves over time.

genomics↗

bioRxiv2018

TRPV1 regulates opioid analgesia during inflammation

Acute inflammation in humans or mice enhances the analgesic properties of opioids. However, the inflammatory transducers that prime opioid receptor signaling in nociceptors are unknown. We found that TRPV1-/- mice are insensitive to peripheral opioid analgesia in an inflammatory pain model. We report that TRPV1 channel activation drives a MAPK signaling pathway accompanied by the shuttling of {beta}-arrestin2 to the nucleus. This shuttling in turn prevents: {beta}-arrestin2-receptor recruitment, subsequent internalization of agonist-bound mu opioid receptor (MOR), and suppression of DAMGO-induced inhibition of N-type calcium current observed upon desensitization. Consequently, inflammation-induced activation of TRPV1 preserves opioid analgesic potency in a mouse model of opioid receptor desensitization. Overall, our work reveals a TRPV1-mediated signaling mechanism, involving {beta}-arrestin2 nuclear translocation, that underlies the peripheral opioid control of inflammatory pain. Our data single out TRPV1 channels as modulators of opioid analgesia.

neuroscience↗