Biology subjects

Rosenberg, J. M.

Publications and source records attributed to Rosenberg, J. M..

3 recordsLinked to original sources

bioRxiv2023

CD4+ T cells are homeostatic regulators during Mtb reinfection

Immunological priming - either in the context of prior infection or vaccination - elicits protective responses against subsequent Mycobacterium tuberculosis (Mtb) infection. However, the changes that occur in the lung cellular milieu post-primary Mtb infection and their contributions to protection upon reinfection remain poorly understood. Here, using clinical and microbiological endpoints in a non-human primate reinfection model, we demonstrate that prior Mtb infection elicits a long-lasting protective response against subsequent Mtb exposure and that the depletion of CD4+ T cells prior to Mtb rechallenge significantly abrogates this protection. Leveraging microbiologic, PET-CT, flow cytometric, and single-cell RNA-seq data from primary infection, reinfection, and reinfection-CD4+ T cell depleted granulomas, we identify differential cellular and microbial features of control. The data collectively demonstrate that the presence of CD4+ T cells in the setting of reinfection results in a reduced inflammatory lung milieu characterized by reprogrammed CD8+ T cell activity, reduced neutrophilia, and blunted type-1 immune signaling among myeloid cells, mitigating Mtb disease severity. These results open avenues for developing vaccines and therapeutics that not only target CD4+ and CD8+ T cells, but also modulate innate immune cells to limit Mtb disease.

immunology↗

bioRxiv2023

Protective intravenous BCG vaccination induces enhanced immune signaling in the airways

Intradermal (ID) Bacillus Calmette-Guerin (BCG) is the most widely administered vaccine in the world. However, ID-BCG fails to achieve the level of protection needed in adults to alter the course of the tuberculosis epidemic. Recent studies in non-human primates have demonstrated high levels of protection against Mycobacterium tuberculosis (Mtb) following intravenous (IV) administration of BCG. However, the protective immune features that emerge following IV BCG vaccination remain incompletely defined. Here we used single-cell RNA-sequencing (scRNAseq) to transcriptionally profile 157,114 unstimulated and purified protein derivative (PPD)-stimulated bronchoalveolar lavage (BAL) cells from 29 rhesus macaques immunized with BCG across routes of administration and doses to uncover cell composition-, gene expression-, and biological network-level signatures associated with IV BCG-mediated protection. Our analyses revealed that high-dose IV BCG drove an influx of polyfunctional T cells and macrophages into the airways. These macrophages exhibited a basal activation phenotype even in the absence of PPD-stimulation, defined in part by IFN and TNF- signaling up to 6 months following BCG immunization. Furthermore, intercellular immune signaling pathways between key myeloid and T cell subsets were enhanced following PPD-stimulation in high-dose IV BCG-vaccinated macaques. High-dose IV BCG also engendered quantitatively and qualitatively stronger transcriptional responses to PPD-stimulation, with a robust Th1-Th17 transcriptional phenotype in T cells, and augmented transcriptional signatures of reactive oxygen species production, hypoxia, and IFN-{gamma} response within alveolar macrophages. Collectively, this work supports that IV BCG immunization creates a unique cellular ecosystem in the airways, which primes and enables local myeloid cells to effectively clear Mtb upon challenge.

immunology↗

bioRxiv2020

K2P channel C-type gating involves asymmetric selectivity filter order-disorder transitions

K2P channels regulate nervous, cardiovascular, and immune system functions1,2 through the action of their selectivity filter (C-type) gate3-6. Although structural studies show K2P conformations that impact activity7-13, no selectivity filter conformational changes have been observed. Here, combining K2P2.1 (TREK-1) X-ray crystallography in different potassium concentrations, potassium anomalous scattering, molecular dynamics, and functional studies, we uncover the unprecedented, asymmetric, potassium-dependent conformational changes underlying K2P C-type gating. Low potassium concentrations evoke conformational changes in selectivity filter strand 1 (SF1), selectivity filter strand 2 (SF2), and the SF2-transmembrane helix 4 loop (SF2-M4 loop) that destroy the S1 and S2 ion binding sites and are suppressed by C-type gate activator ML335. Shortening the uniquely long SF2-M4 loop to match the canonical length found in other potassium channels or disrupting the conserved Glu234 hydrogen bond network supporting this loop blunts C-type gate response to various physical and chemical stimuli. Glu234 network destabilization also compromises ion selectivity, but can be reversed by channel activation, indicating that the ion binding site loss reduces selectivity similar to other channels14. Together, our data establish that C-type gating occurs through potassium-dependent order-disorder transitions in the selectivity filter and adjacent loops that respond to gating cues relayed through the SF2-M4 loop. These findings underscore the potential for targeting the SF2-M4 loop for the development of new, selective K2P channel modulators.

biophysics↗