Existing antibodies (Abs) have varied effects on humoral immunity during subsequent infections. Here, we leveraged in vivo systems that allow precise control of antigen-specific Abs and B cells to examine the impact of Ab dose, affinity, and specificity in directing B cell activation and differentiation. Abs competing with the B cell receptor (BCR) epitope showed affinity-dependent suppression.
View Article and Find Full Text PDFAcute kidney injury (AKI) disrupts energy metabolism. Targeting metabolism through AMP-activated protein kinase (AMPK) may alleviate AKI. ATX-304, a pan-AMPK activator, was evaluated in C57Bl/6 mice and tubular epithelial cell (TEC) cultures.
View Article and Find Full Text PDFTransforming growth factor-β (TGFβ) drives fibrosis and disease progression in a number of chronic disorders, but targeting this ubiquitously expressed cytokine may not yield a viable and safe antifibrotic therapy. Here, we sought to identify alternative ways to inhibit TGFβ signaling using human hepatic stellate cells and macrophages from humans and mice in vitro, as well as mouse models of liver, kidney, and lung fibrosis. We identified Mer tyrosine kinase (MERTK) as a TGFβ-inducible effector of fibrosis that was up-regulated during fibrosis in multiple organs in three mouse models.
View Article and Find Full Text PDFIntragenic CpG dinucleotides are tightly conserved in evolution yet are also vulnerable to methylation-dependent mutation, raising the question as to why these functionally critical sites have not been deselected by more stable coding sequences. We previously showed in cell lines that altered exonic CpG methylation can modify promoter start sites, and hence protein isoform expression, for the human TP53 tumor suppressor gene. Here we extend this work to the in vivo setting by testing whether synonymous germline modifications of exonic CpG sites affect murine development, fertility, longevity, or cancer incidence.
View Article and Find Full Text PDFIntroduction: Germline CARD11 gain-of-function (GOF) mutations cause B cell Expansion with NF-κB and T cell Anergy (BENTA) disease, whilst somatic GOF CARD11 mutations recur in diffuse large B cell lymphoma (DLBCL) and in up to 30% of the peripheral T cell lymphomas (PTCL) adult T cell leukemia/lymphoma (ATL), cutaneous T cell lymphoma (CTCL) and Sezary Syndrome. Despite their frequent acquisition by PTCL, the T cell-intrinsic effects of CARD11 GOF mutations are poorly understood.
Methods: Here, we studied B and T lymphocytes in mice with a germline Nethyl-N-nitrosourea (ENU)-induced Card11 mutation identical to a mutation identified in DLBCL and modifying a conserved region of the CARD11 coiled-coil domain recurrently mutated in DLBCL and PTCL.
Germinal centers (GCs) that form within lymphoid follicles during antibody responses are sites of massive cell death. Tingible body macrophages (TBMs) are tasked with apoptotic cell clearance to prevent secondary necrosis and autoimmune activation by intracellular self antigens. We show by multiple redundant and complementary methods that TBMs derive from a lymph node-resident, CD169-lineage, CSF1R-blockade-resistant precursor that is prepositioned in the follicle.
View Article and Find Full Text PDFDietary components and metabolites have a profound impact on immunity and inflammation. Here, we investigated how sensing of cholesterol metabolite oxysterols by γδ T cells impacts their tissue residency and function. We show that dermal IL-17-producing γδ T (Tγδ17) cells essential for skin-barrier homeostasis require oxysterols sensing through G protein receptor 183 (GPR183) for their development and inflammatory responses.
View Article and Find Full Text PDFImmunoglobulin A (IgA) secretion by plasma cells, terminally differentiated B cells residing in the intestinal lamina propria, assures microbiome homeostasis and protects the host against enteric infections. Exposure to diet-derived and commensal-derived signals provides immune cells with organizing cues that instruct their effector function and dynamically shape intestinal immune responses at the mucosal barrier. Recent data have described metabolic and microbial inputs controlling T cell and innate lymphoid cell activation in the gut; however, whether IgA-secreting lamina propria plasma cells are tuned by local stimuli is completely unknown.
View Article and Find Full Text PDFAMP-activated protein kinase (AMPK) is a master regulator of cellular energy homeostasis and a therapeutic target for metabolic diseases. Co/post-translational N-myristoylation of glycine-2 (Gly2) of the AMPK β subunit has been suggested to regulate the distribution of the kinase between the cytosol and membranes through a "myristoyl switch" mechanism. However, the relevance of AMPK myristoylation for metabolic signaling in cells and in vivo is unclear.
View Article and Find Full Text PDFThe association between cancer and autoimmune disease is unexplained, exemplified by T cell large granular lymphocytic leukemia (T-LGL) where gain-of-function (GOF) somatic STAT3 mutations correlate with co-existing autoimmunity. To investigate whether these mutations are the cause or consequence of CD8 T cell clonal expansions and autoimmunity, we analyzed patients and mice with germline STAT3 GOF mutations. STAT3 GOF mutations drove the accumulation of effector CD8 T cell clones highly expressing NKG2D, the receptor for stress-induced MHC-class-I-related molecules.
View Article and Find Full Text PDFMevalonate kinase deficiency (MKD) is characterized by recurrent fevers and flares of systemic inflammation, caused by biallelic loss-of-function mutations in MVK. The underlying disease mechanisms and triggers of inflammatory flares are poorly understood because of the lack of in vivo models. We describe genetically modified mice bearing the hypomorphic mutation p.
View Article and Find Full Text PDFThe notion that mobile units of nucleic acid known as transposable elements can operate as genomic controlling elements was put forward over six decades ago. However, it was not until the advancement of genomic sequencing technologies that the abundance and repertoire of transposable elements were revealed, and they are now known to constitute up to two-thirds of mammalian genomes. The presence of DNA regulatory regions including promoters, enhancers and transcription-factor-binding sites within transposable elements has led to the hypothesis that transposable elements have been co-opted to regulate mammalian gene expression and cell phenotype.
View Article and Find Full Text PDFMouse haematopoietic stem cells (HSCs) first emerge at embryonic day 10.5 (E10.5), on the ventral surface of the dorsal aorta, by endothelial-to-haematopoietic transition.
View Article and Find Full Text PDFGerminal centers (GCs), transient structures within B cell follicles and central to affinity maturation, require the coordinated behavior of T and B cells. IL-21, a pleiotropic T cell-derived cytokine, is key to GC biology through incompletely understood mechanisms. By genetically restricting production and receipt of IL-21 in vivo, we reveal how its independent actions on T and B cells combine to regulate the GC.
View Article and Find Full Text PDFThe proliferation and differentiation of antigen-specific B cells, including the generation of germinal centers (GC), are prerequisites for long-lasting, antibody-mediated immune protection. Affinity for antigen determines B cell recruitment, proliferation, differentiation, and competitiveness in the response, largely through determining access to T cell help. However, how T cell-derived signals contribute to these outcomes is incompletely understood.
View Article and Find Full Text PDFViral mutations are an emerging concern in reducing SARS-CoV-2 vaccination efficacy. Second-generation vaccines will need to elicit neutralizing antibodies against sites that are evolutionarily conserved across the sarbecovirus subgenus. Here, we immunized mice containing a human antibody repertoire with diverse sarbecovirus receptor-binding domains (RBDs) to identify antibodies targeting conserved sites of vulnerability.
View Article and Find Full Text PDFGerminal center (GC) B cells are the source of the high-affinity, class-switched antibodies required for protective immunity. The unique biology of GC B cells involves iterative rounds of antibody gene somatic hypermutation coupled to multiple selection and differentiation pathways. Recent advances in areas such as single cell and gene editing technologies have shed new light upon these complex and dynamic processes.
View Article and Find Full Text PDFAntibodies against coronavirus spike protein potently protect against infection and disease, but whether such protection can be extended to variant coronaviruses is unclear. This is exemplified by a set of iconic and well-characterized monoclonal antibodies developed after the 2003 SARS outbreak, including mAbs m396, CR3022, CR3014 and 80R, which potently neutralize SARS-CoV-1, but not SARS-CoV-2. Here, we explore antibody engineering strategies to change and broaden their specificity, enabling nanomolar binding and potent neutralization of SARS-CoV-2.
View Article and Find Full Text PDFOsteocytes are master regulators of the skeleton. We mapped the transcriptome of osteocytes from different skeletal sites, across age and sexes in mice to reveal genes and molecular programs that control this complex cellular-network. We define an osteocyte transcriptome signature of 1239 genes that distinguishes osteocytes from other cells.
View Article and Find Full Text PDFRegulation of the anti-apoptotic BCL2 protein determines cell survival and is frequently abnormal in B cell lymphomas. An evolutionarily conserved post-translational mechanism for over-expression of BCL2 in human B cell lymphomas and the BCL2 paralogue CED-9 in Caenorhabditis elegans results from loss-of-function mutations in human FBXO10 and its C.elegans paralogue DRE-1, a BCL2/CED-9-binding subunit of the SKP-CULLIN-FBOX (SCF) ubiquitin ligase.
View Article and Find Full Text PDFPositive selection of high-affinity B cells within germinal centers (GCs) drives affinity maturation of antibody responses. Here, we examined the mechanism underlying the parallel transition from immunoglobulin M (IgM) to IgG. Early GCs contained mostly unswitched IgM B cells; IgG B cells subsequently increased in frequency, dominating GC responses 14-21 days after antigen challenge.
View Article and Find Full Text PDF