Biology subjects

Heinz, G. A.

Publications and source records attributed to Heinz, G. A..

7 recordsLinked to original sources

bioRxiv2023

IL-33 controls IL-22-dependent antibacterial defense by modulating the microbiota

IL-22 plays a critical role in defending against mucosal infections, but how IL-22 production is regulated is incompletely understood. Here, we show that mice lacking IL-33 or its receptor ST2 (IL-1RL1) were more resistant to Streptococcus pneumoniae lung infection than wild-type animals, and that single nucleotide polymorphisms in IL33 and IL1RL1 were associated with pneumococcal pneumonia in humans. The effect of IL-33 on S. pneumoniae infection was mediated by negative regulation of IL-22 production in innate lymphoid cells (ILCs), but independent of ILC2s as well as IL-4 and IL-13 signaling. Moreover, IL-33s influence on antibacterial defense was dependent on housing conditions of the mice, and mediated by the modulatory effect of IL-33 on the microbiota. Collectively, we provide insight into the bidirectional crosstalk between the innate immune system and the microbiota. We identify a mechanism, dependent on both genetic and environmental factors, that impacts the efficacy of antibacterial immune defense and thus susceptibility to pneumonia. SIGNIFICANCE STATEMENTLower respiratory tract infections are the fifth leading cause of death. Here, we describe a mechanism influenced by genetic and environmental factors that affects the efficacy of pulmonary antibacterial immune responses. We show that IL-33 controls antibacterial defense by regulating the production of IL-22, a cytokine with known functions in antimicrobial immunity in lungs. The effect of IL-33 on IL-22-dependent defense was influenced by the hygienic status of the mice and mediated by IL-33s modulatory effect on the animal microbiota. In addition, genetic variation in genes involved in IL-33 signaling was associated with bacterial pneumonia in humans. Our findings may be important for our understanding of the factors influencing predisposition to lower respiratory tract infections.

immunology↗

bioRxiv2023

MicroRNA-221/222-expression in HSC and MPP safeguards their quiescence and multipotency by downregulating stress-independent and dependent expression of IEG and of several myelo/granulopoiesis-enhancing target genes.

The microRNA cluster-221/222 is expressed in hematopoietic stem cells (HSC) and multipotent progenitors (MPP). To study its function in hematopoiesis, we generated mice, in which this cluster is selectively deleted by Vav-cre in HSC and, thus, in all hematopoietic cells. Fluorescence-activated cell sorting analyses of the lineage-negative HSC and MPP compartments in bone marrow at unperturbed, steady state hematopoiesis detect strong activation of HSC to MPP, as well as increased granulocytes in the periphery, induced by miR-221/222-deficiency. Short-term social stress on mice also activates HSC to MPP, but the time of stress is too short to detect further increases in granulocyte numbers. Single cell deep mRNA sequencing identifies Fos as direct, and Jun as well as six other immediate early genes (IEG) as indirect targets of miR-221/222 at unperturbed hematopoiesis. Three of these IEG - Klf6, Nr4a1 and Zfp36 - have previously been found to influence myelo/granulopoiesis. Short stress induces higher levels of the same, and an even larger number of IEGs, now also in MPP, indicating, that stress and miR-221/222 both activate HSC to MPP by IEG upregulation in perturbed hematopoiesis. Furthermore, combined stress and miR-221/222-deficiency rapidly increase numbers of myelo/granulocyte progenitors (MEP, GMP) in bone marrow. Additional indirect miR-221/222-targets become detectable in MPP, of which H3f3b has previously been found to influence myelopoiesis. In serial transplantations, miR-221/222-deficient HSC retain their capacity to home to, and become resident in bone marrow, but they loose their lymphopoietic capacities, thus their multipotency. Our results suggest, that miR-221/222-expression in HSC and MPP safeguards their quiescence and multipotency by downregulating the expression of IEG and of myelo/granulopoiesis-enhancing target genes. Since miR-221/222 is also expressed in human HSC and MPP, its expression should improve clinical settings of human bone marrow transplantations.

immunology↗

bioRxiv2021

Induction of cross-reactive antibody responses against the RBD domain of the spike protein of SARS-CoV-2 by commensal microbiota

The commensal microflora is a source for multiple antigens that may induce cross-reactive antibodies against host proteins and pathogens. However, whether commensal bacteria can induce cross-reactive antibodies against SARS-CoV-2 remains unknown. Here we report that several commensal bacteria contribute to the generation of cross-reactive IgA antibodies against the receptor-binding domain (RBD) of the SARS-CoV-2 Spike protein. We identified SARS-CoV-2 unexposed individuals with RBD-binding IgA antibodies at their mucosal surfaces. Conversely, neutralising monoclonal anti-RBD antibodies recognised distinct commensal bacterial species. Some of these bacteria, such as Streptococcus salivarius, induced a cross-reactive anti-RBD antibodies upon supplementation in mice. Conversely, severely ill COVID-19 patients showed reduction of Streptococcus and Veillonella in their oropharynx and feces and a reduction of anti-RBD IgA at mucosal surfaces. Altogether, distinct microbial species of the human microbiota can induce secretory IgA antibodies cross-reactive for the RBD of SARS-CoV-2.

microbiology↗

bioRxiv2020

Combining segmental bulk- and single-cell RNA-sequencing to define the chondrocyte gene expression signature in the murine knee joint

ObjectiveDue to the small size of the murine knee joint, extracting the chondrocyte transcriptome from articular cartilage (AC) is a major technical challenge. In this study, we demonstrate a new and pragmatic approach of combining bulk RNA-sequencing (RNA-seq) and single cell (sc)RNA-seq to address this problem. DesignWe propose a new cutting strategy of the murine femur which produces three segments with a predictable mixed cell populations, where one segment contains AC and growth plate (GP) chondrocytes, another contains GP chondrocytes, and the last segment contains only bone and bone marrow. We analysed the bulk RNA-seq of the different segments to find common and distinct genes between the segments. Then, the segment containing AC chondrocytes was digested and analysed via scRNA-seq. ResultsDifferential expression analysis using bulk RNA-seq identified 350 candidate chondrocyte gene in the AC segment. Gene set enrichment analysis of these genes revealed biological processes related- and non-related to chondrocytes, including, cartilage development (adj. p-value: 3.45E-17) and endochondral bone growth (adj. p-value 1.22E-4), respectively. ScRNA-seq of the AC segment found a cluster of 131 cells containing mainly chondrocytes. This cluster had 759 differentially expressed genes which enriched for extracellular matrix organisation (adj. p-value 7.76E-40) and other joint development processes. The intersection of the gene sets of bulk- and scRNA-seq contained 75 genes, where all but ten genes were previously implicated in cartilage homeostasis or osteoarthritis (OA) progression. ConclusionsOur approach has the potential to detect the scarce disease phenotypes of chondrocytes in murine OA models.

molecular biology↗

bioRxiv2020

Mobilization of tissue-resident memory CD4+ T lymphocytes and their contribution to a systemic secondary immune reaction

While it is generally accepted that tissue-resident memory T lymphocytes protect host tissues from secondary immune challenges, it is unclear whether, and if so, how they contribute to systemic secondary immune responses. Here we show that in human individuals with an established immune memory to measles, mumps and rubella viruses, when challenged with the measles-mumps-rubella (MMR) vaccine again, tissue-resident memory CD4+ T cells are mobilized into the blood within 16 to 48 hours after vaccination. These cells then leave the blood again, and apparently contribute to the systemic secondary immune reaction, as is evident from the representation of mobilized T cell receptor V{beta} clonotypes among newly generated circulating memory T lymphocytes, from day 7 onwards. Mobilization of the tissue-resident memory T cells is cognate, in that memory T lymphocytes recognizing other antigens, e.g. tetanus toxin, are not mobilized, unless they cross-react with the vaccine. These data originally demonstrate the essential contribution of tissue-resident memory T cells to secondary systemic immune responses, confirming that immunological memories to systemic pathogens are maintained (also) by tissue-resident memory T cells. In practical terms, the present work defines day 1 to 2 after antigenic challenge as a time window to assess the entire immunological T cell memory for a certain pathogen, including mobilized tissue-resident memory T cells, and its correlates of effectivity. Capsule summaryThe study demonstrates the rapid and cognate mobilization of tissue-resident memory CD4+ T cells into the blood upon antigenic rechallenge, and their contribution to secondary systemic immune responses.

immunology↗

bioRxiv2019

Antigen-driven PD1+Tox+Eomes+ and PD1+Tox+BHLHE40+ synovial T lymphocytes regulate chronic inflammation in situ

Introduction/AbstractT lymphocytes accumulate in inflamed tissues of patients with chronic inflammatory diseases (CIDs) and express pro-inflammatory cytokines upon re-stimulation in vitro1-29. Further, a significant genetic linkage to MHC genes suggests that T lymphocytes play an important role in the pathogenesis of CIDs including juvenile idiopathic arthritis (JIA)30-33. However, the functions of T lymphocytes in established disease remain elusive. Here we dissect the heterogeneity of synovial T lymphocytes in JIA patients by single cell RNA-sequencing. We identify subpopulations of T lymphocytes expressing genes reflecting recent activation by antigen in situ. A PD-1+TOX+EOMES+ population of CD4+ T lymphocytes expressed immune regulatory genes and chemoattractant genes for myeloid cells. A PD-1+TOX+BHLHE40+ population of CD4+, and a mirror population of CD8+ T lymphocytes expressed genes driving inflammation, and genes supporting B lymphocyte activation. This analysis points out that multiple types of T lymphocytes have to be targeted for therapeutic regeneration of tolerance in arthritis.

immunology↗

bioRxiv2019

Discrete populations of isotype-switched memory B lymphocytes are maintained in murine spleen and bone marrow

Here we describe tissue-resident memory B lymphocytes of spleen and bone marrow. Single cell transcriptomes and B cell receptor repertoires identify several exclusive populations of isotype-switched memory B cells (Bsm) in murine spleen and bone marrow, and one interconnected population of 10-20%. A population of marginal zone-like Bsm is located exclusively in the spleen while a novel population of quiescent Bsm is located exclusively in the bone marrow. Cells of two further populations, present in both, spleen and bone marrow, differ in repertoire between the two organs, i.e. are resident as well. Finally, another interconnected population of Bsm of the B1 lineage is present in spleen and bone marrow. In the bone marrow, all Bsm individually dock onto VCAM1+ stromal cells, resting in terms of activation, proliferation and mobility. The discrete B cell memory of bone marrow may be key to rapid secondary humoral responses to systemic antigens.

immunology↗