Biology subjects

Bailey, H.

Publications and source records attributed to Bailey, H..

7 recordsLinked to original sources

bioRxiv2026

Inflammatory signaling differentially changes chromatin accessibility and gene expression of the PD- associated kinase LRRK2 between human and mice

The genomic locus that encodes the Leucine-rich repeat kinase 2 (LRRK2) gene is highly pleiotropic, being associated with both Parkinsons disease (PD) and Crohns disease (CD). Coding variants associated with risk of PD and CD act as gain of function kinase mutations increasing phosphorylation of RAB substrates, and non-coding variants in the promoter region of LRRK2 increase expression of the gene, notably in immune cells. If regulation of LRRK2 expression is a causal contributor to age-related diseases, it is important to understand the mechanism(s) by which LRRK2 is regulated, particularly in the context of inflammation. Here, we show that interferon-{gamma} exposure induces robust LRRK2 activation in human iPSC-derived microglia through signaling of the Janus-activated Kinase complex to phosphorylate STAT1, which then binds to the LRRK2 promoter and is associated with remodeling of chromatin structure in this genomic locus. Additional regulatory mechanisms include the stress-induced transcription factor and long non-coding RNA encoded at the same locus, resulting in increased LRRK2 mRNA levels. We also show evidence of the same effect in acutely cultured human brain slices. While we were unable to demonstrate any induction of Lrrk2 mRNA in the mouse brain, the introduction of a human bacterial artificial chromosome transgene into the mouse genome recapitulated sensitivity to interferon-{gamma} in microglia. A comparative genomic analysis across mammals suggests that these species differences are driven by regulatory regions upstream of LRRK2 that are specific to anthropoid primates. These results demonstrate that there are differences between species in how genes associated with human diseases are regulated and provide important information that should be incorporated in disease modeling.

neuroscience↗

bioRxiv2025

Phosphoribosyl ubiquitination of SNARE proteins regulate autophagy in Legionella infection

Legionella pneumophila is an intracellular pathogen that causes Legionnaires disease. The bacteria releases effector proteins some of which remodel the host autophagic-lysosomal pathways. One effector is RavZ, which delipidates ATG8 proteins, making Legionella-infected cells deficient in autophagy. Here we show that SidE effectors mediate the phosphoribosyl ubiquitination (PR-Ub) of autophagic SNARE proteins STX17 and SNAP29. STX17 modification induces recruitment of STX17+ membranes from the endoplasmic reticulum to Legionella-containing phagosomes to form replicative vacuoles. Using proximity labeling, biochemistry and Legionella infection studies, we have discovered a mechanism by which autophagy is hijacked by bacteria to recruit ER membranes to the bacterial vacuole which has autophagy markers but do not fuse with lysosomes. Mass spectrometric identification of PR-Ub sites and mutational studies show that PR-Ub modification of STX17 alters its interaction with ATG14L, which drives the recruitment of ER membranes to the bacterial vacuole in a PI3K dependent manner. On the other hand, PR-Ub of SNAP29 inhibits the formation of the autophagosomal SNARE complex (STX17-SNAP29-VAMP8) by steric hindrance, thereby preventing the fusion of bacterial vacuoles with lysosomes.

cell biology↗

bioRxiv2024

Therapeutic DNA Vaccine Targeting Mycobacterium tuberculosis Persisters Shortens Curative Tuberculosis Treatment

Mycobacterium tuberculosis (Mtb) is one of the leading infectious causes of death worldwide. There is no available licensed therapeutic vaccine that shortens active tuberculosis (TB) disease drug treatment and prevents relapse, despite the World Health Organizations calls. Here, we show that an intranasal DNA vaccine containing a fusion of the stringent response relMtb gene with the gene encoding the immature dendritic cell-targeting chemokine, MIP-3/CCL20, shortens the duration of curative TB treatment in immunocompetent mice. Compared to the first-line regimen for drug-susceptible TB alone, our novel adjunctive vaccine induced greater RelMtb-specific T-cell responses associated with optimal TB control in spleen, blood, lungs, mediastinal lymph nodes, and bronchoalveolar lavage (BAL) fluid. These responses were sustained, if not augmented, over time. It also triggered more effective dendritic cell recruitment, activation, and colocalization with T cells, implying enhanced crosstalk between innate and adaptive immunity. Moreover, it potentiated a 6-month TB drug-resistant regimen, rendering it effective across treatment regimens, and also showed promising results in CD4+ knockout mice, perhaps due to enhanced Rel-specific CD8+ T-cell responses. Notably, our novel fusion vaccine was also immunogenic in nonhuman primates, the gold standard animal model for TB vaccine studies, eliciting antigen-specific T-cell responses in blood and BAL fluid analogous to those observed in protected mice. Our findings have critical implications for therapeutic TB vaccine clinical development in immunocompetent and immunocompromised populations and may serve as a model for defining immunological correlates of therapeutic vaccine-induced protection. One sentence summaryA TB vaccine shortens curative drug treatment in mice by eliciting strong TB-protective immune responses and induces similar responses in macaques.

immunology↗

bioRxiv2024

Pharmacological inhibition of macrophage triglyceride biosynthesis pathways does not improve Mycobacterium tuberculosis control in infected mice

Triglyceride rich macrophages (foam cells) are a hallmark of necrotic granulomas in tuberculosis, and multiple antimicrobial functions are down-regulated in these cells. In this study, we assessed the ability of two different compounds to reduce triglyceride content and intracellular burden in Mycobacterium tuberculosis (Mtb)-infected macrophages: A-922500 (DGATi), an inhibitor of diacylglycerol acyltransferase 1, an enzyme involved in triglyceride synthesis; and LY2584702 (p70S6Ki), an inhibitor of p70 S6 kinase, a serine/threonine kinase involved in mTORC-1dependent lipid biogenesis. Additionally, we evaluated the adjunctive activity of these inhibitors as host-directed therapies against chronic Mtb infection in C3HeB/FeJ mice. DGATi and p70S6Ki significantly reduced the lipid content and bacillary burden in Mtb-infected human monocyte-derived macrophages. In Mtb-infected mice, each inhibitor reduced the triglyceride content (P[≤] 0.0001) in cells from bronchoalveolar lavage samples. Adjunctive treatment of DGATi with isoniazid and p70S6Ki monotherapy reduced the lipid droplet content (P[≤] 0.05) within lung macrophages of Mtb-infected mice. However, neither inhibitor reduced the lung bacterial burden in Mtb-infected mice alone or in combination with isoniazid, and they did not alter lung inflammation. These findings provide further insights into the role of foam cells in tuberculosis pathogenesis and the utility of interventions targeting these cell populations as adjunctive host-directed therapies.

pharmacology and toxicology↗

bioRxiv2022

Lead (Pb) impairs thyroid hormone mediated changes in brain development and body length in Xenopus laevis tadpoles

Lead (Pb) poisoning during early development is associated with behavioral and cognitive deficits, but the specific mechanisms by which Pb impairs brain development are not fully understood. One potential mechanism is that Pb poisoning may impair thyroid hormone (TH)- mediated changes in brain development To address this issue, we performed experiments to assess the effects of Pb poisoning on (TH) -dependent changes in cellular and molecular mechanisms in the developing Xenopus laevis tadpole brain. We treated stage 48 tadpoles to combinations of 1000 ppb Pb bath for seven days and added one of three different concentrations of thyroxine (T4) for the final two days of treatment. We found that lead exposure decreased body length, including in T4-treated tadpoles. We also performed immuno-staining for proliferative marker pH3 and found that Pb disrupts T4-induced increases in neuronal proliferation. Finally, we used syGlass VR data visualization software to measure volume of the forebrain, midbrain, and hindbrain in 3D and found that Pb exposure impaired T4-mediated changes in brain volume. Last, we found that Pb poisoning reduced the T4-mediated increase in proliferating cell nuclear antigen (PCNA), a TH-sensitive gene. These results illustrate that Pb poisoning impairs some TH-dependent changes in the developing brain.

pharmacology and toxicology↗

bioRxiv2021

Shiitake mycelium fermentation improves digestibility, nutritional value, flavor and functionality of plant proteins

Plant proteins can serve as inexpensive and environmentally friendly meat-replacements. However, poor taste characteristics and relatively low nutritional value prevent their full acceptance as meat substitutes. Fermentation of food has been historically used to improve the quality of foods. In this work we describe the improvement in digestibility, nutritional value, physical properties, and organoleptic characteristics, of a pea and rice protein concentrate blend through fermentation with shiitake mushroom mycelium. Ileal digestibility pig studies show increases in the DIAAS for the shiitake fermented pea and rice protein blend turning the blend into an "excellent source" of protein for humans. The fermentation also increases the solubility of the protein blend and reduces the content of the antinutrient compounds phytates and protease inhibitor. Mass spectrometry and sensory analyses of fermented protein blend indicates that fermentation leads to a reduction in off-note compounds substantially improving its organoleptic performance.

bioengineering↗

bioRxiv2020

Naturally occurring cobalamin (B12) analogs can function as cofactors for human methylmalonyl-CoA mutase

Cobalamin, commonly known as vitamin B12, is an essential micronutrient for humans because of its role as an enzyme cofactor. Cobalamin is one of over a dozen structurally related compounds - cobamides - that are found in food and are produced by microorganisms in the human gut. Very little is known about how different cobamides affect B12-dependent metabolism in human cells. Here, we test in vitro how diverse cobamide cofactors affect the function of methylmalonyl-CoA mutase (MMUT), one of two cobalamin-dependent enzymes in humans. We find that, although cobalamin is the most effective cofactor for MMUT, multiple cobamides support MMUT function with differences in binding affinity (Kd), binding kinetics (kon), and concentration dependence during catalysis (KM, app). Additionally, we find that six disease-associated MMUT variants that cause cobalamin-responsive impairments in enzymatic activity also respond to other cobamides, with the extent of catalytic rescue dependent on the identity of the cobamide. Our studies challenge the exclusive focus on cobalamin in the context of human physiology, indicate that diverse cobamides can support the function of a human enzyme, and suggest future directions that will improve our understanding of the roles of different cobamides in human biology.

biochemistry↗