Biology subjects

Berry, S. B.

Publications and source records attributed to Berry, S. B..

6 recordsLinked to original sources

bioRxiv2026

Host control of Mycobacterium tuberculosis infection is not influenced by the gut microbiome

Tuberculosis (TB) is a life-threatening disease with heterogenous presentation. Approximately one-quarter of the global population is infected with Mycobacterium tuberculosis (Mtb), yet a much smaller fraction develops active TB disease. Host genetics, immune system function, and environmental factors have all been implicated in susceptibility to Mtb, yet no one factor fully explains TB heterogeneity. Strikingly, many of these same factors are linked to gut microbiome composition, which is intimately linked to systemic development of the immune system. Antibiotic treated mouse models suggest that increased gut microbiota diversity is protective against Mtb infection. In contrast, Helicobacter hepaticus colonization is correlated with exacerbated Mtb burden. However, antibiotics can have both microbial and nonmicrobial targets and studies to date have not deconvoluted these effects. Focused testing of specific microbiome members has been impossible without a gnotobiotic model for Mtb. Here, we develop the first gnotobiotic mouse model for Mtb infection and test how microbial diversity in the gut microbiome impacts host susceptibility to Mtb. Surprisingly, after intranasal challenge with Mtb, germ-free wild type mice had no difference in lung burden when compared to mice born with either a defined gut microbiome community (OMM-12) or a diverse, conventional microbiota. H. hepaticus gut colonization of OMM-12 and conventional mice also did not impact Mtb burden in the lungs in this controlled setting. H. hepaticus colonization of the gut did perturb lung immune responses associated with TB infection control. CD4+ T cells were decreased, CD8+ T cells were increased, and IL-6 production was decreased. While the gut microbiome may yet play a role in immune compromised mouse models or human disease, comparing drastically different gut microbiotas in gnotobiotically controlled C57BL/6 mice did not yield any evidence of alteration in Mtb lung burden. The hosts unique immune response to Mtb may in part make the pathogen resistant to immune disruption caused by gut microbiome changes.

microbiology↗

bioRxiv2024

Methylglyoxal is an antibacterial effector produced by macrophages during infection

Infected macrophages transition into aerobic glycolysis, a metabolic program crucial for control of bacterial infection. However, antimicrobial mechanisms supported by aerobic glycolysis are unclear. Methylglyoxal is a highly toxic aldehyde that modifies proteins and DNA and is produced as a side-product of glycolysis. Here we show that despite the toxicity of this aldehyde, infected macrophages generate high levels of methylglyoxal during aerobic glycolysis while downregulating the detoxification system. We use targeted mutations in mice to modulate methylglyoxal generation and show that reducing methylglyoxal production by the host promotes survival of Listeria monocytogenes and Mycobacterium tuberculosis, whereas increasing methylglyoxal levels improves control of bacterial infection. Furthermore, we show that bacteria that are unable to detoxify methylglyoxal are avirulent and experience up to 1000-fold greater genomic mutation frequency during infection. Taken together, these results suggest that methylglyoxal is an antimicrobial innate immune effector that defends the host against bacterial pathogens.

microbiology↗

bioRxiv2023

Alpha-toxin elicited CX3CL1-release via ADAM10 in Staphylococcus aureus pneumoniaimpairs bactericidal function of human monocytes

Staphylococcus aureus is an important human pathogen causing severe invasive infections. Pathogenesis is attributed to a wide array of virulence factors, including several potent exotoxins such as the pore-forming alpha-toxin. In this study, we found that patients with S. aureus respiratory tract infections had elevated CX3CL1 levels in airway fluid and plasma. Using humanized organotypic lung models, we observed that stimulation of lung epithelium with alpha-toxin induce an intensified CX3CL1 expression apically in the epithelium as well as the release of CX3CL1. Blocking alpha-toxin or ADAM10 activity in organotypic lung using an alpha-toxin-blocking antibody or a specific ADAM-10 inhibitor confirmed their role in modulating CX3CL1 cleavage and release. Analyses of CD14+ human monocytes in combination with a CX3CR1 inhibitor revealed that alpha-toxin-mediated CX3CL1 release induce CX3CL1-dependent chemotaxis. In line with these data, lung tissue from patients with S. aureus respiratory tract infection showed elevated CX3CL1 and CD14 staining as compared to tissue from patients with non-infectious lung diseases. Functional studies of monocytes showed that CX3CL1 released by lung models resulted in upregulated CD83 and downregulated CD86, as well as impaired killing of phagocytosed S. aureus. Furthermore, stimulation of monocytes with soluble CX3CL1 hampered their reactive-oxygen and nitric-oxide production. Taken together, our data show that S. aureus triggers the release of lung epithelial CX3CL1; a process found to be dependent on the alpha-toxins effect on ADAM10 mediating cytotoxicity and resulting in impaired monocyte phagocytic killing. Hence, we identify an immunomodulatory effect of alpha-toxin involving the CX3CL1-ADAM10 axis extending beyond the cytolysis function.

microbiology↗

bioRxiv2020

Localized cell-surface sampling of a secreted factor using cell-targeting beads

Intercellular communication through the secretion of soluble factors plays a vital role in a wide range of biological processes (e.g., homeostasis, immune response), yet identification and quantification of many of these factors can be challenging due to their degradation or sequestration in cell culture media prior to analysis. Here, we present a customizable bead-based system capable of simultaneously binding to live cells (through antibody-mediated cell-tethering) and capturing cell-secreted molecules. Our functionalized beads capture secreted molecules (e.g., hepatocyte growth factor secreted by fibroblasts) that are diminished when sampled via traditional supernatant analysis techniques (p < 0.05), effectively rescuing reduced signal in the presence of neutralizing components in the cell culture media. Our system enables capture and analysis of molecules integral to chemical communication that would otherwise be markedly decreased prior to analysis. For Table of Contents Only O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=101 SRC="FIGDIR/small/147140v2_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@17fbf42org.highwire.dtl.DTLVardef@1e5b810org.highwire.dtl.DTLVardef@972783org.highwire.dtl.DTLVardef@1a32eb0_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2020

A modular microscale granuloma model for immune-microenvironment signaling studies in vitro

Tuberculosis (TB) is one of the most potent infectious diseases in the world, causing more deaths than any other single infectious agent. TB infection is caused by inhalation of Mycobacterium tuberculosis (Mtb) and subsequent phagocytosis and migration into the lung tissue by innate immune cells (e.g., alveolar macrophages, neutrophils, dendritic cells), resulting in the formation of a fused mass of immune cells known as the granuloma. Considered the pathological hallmark of TB, the granuloma is a complex microenvironment that is crucial for pathogen containment as well as pathogen survival. Disruption of the delicate granuloma microenvironment via numerous stimuli, such as variations in cytokine secretions, nutrient availability, and the makeup of immune cell population, can lead to an active infection. Herein, we present a novel in vitro model to examine the soluble factor signaling between a mycobacterial infection and its surrounding environment. Adapting a newly developed suspended microfluidic platform, known as Stacks, we established a modular microscale infection model containing human immune cells and a model mycobacterial strain that can easily integrate with different microenvironmental cues through simple spatial and temporal "stacking" of each module of the platform. We validate the establishment of suspended microscale (4 L) infection cultures that secrete increased levels of proinflammatory factors IL-6, VEGF, and TNF upon infection and form 3D aggregates (granuloma model) encapsulating the mycobacteria. As a proof of concept to demonstrate the capability of our platform to examine soluble factor signaling, we cocultured an in vitro angiogenesis model with the granuloma model and quantified morphology changes in endothelial structures as a result of culture conditions (P < 0.05 when comparing infected vs. uninfected coculture systems). We envision our modular in vitro granuloma model can be further expanded and adapted for studies focusing on the complex interplay between granulomatous structures and their surrounding microenvironment, as well as a complementary tool to augment in vivo signaling and mechanistic studies.

bioengineering↗

bioRxiv2018

Open channel droplet-based microfluidics

Droplet-based microfluidics enables compartmentalization and controlled manipulation of small volumes. Open microfluidics provides increased accessibility, adaptability, and ease of manufacturing compared to closed microfluidic platforms. Here, we begin to build a toolbox for the emerging field of open channel droplet-based microfluidics, combining the ease of use associated with open microfluidic platforms with the benefits of compartmentalization afforded by droplet-based microfluidics. We develop fundamental microfluidic features to control droplets flowing in an immiscible carrier fluid within open microfluidic systems. Our systems use capillary flow to move droplets and carrier fluid through open channels and are easily fabricated through 3D printing, micromilling, or injection molding; further, droplet generation can be accomplished by simply pipetting into the open channel. We demonstrate droplet incubation and transport for downstream experimentation and tunable droplet splitting in open channels driven by capillary flow. Potential applications of our toolbox for droplet manipulation in open channels include cell culture and analysis, on-chip microscale reactions, and reagent delivery.

bioengineering↗