A fundamental problem in biomedical research is the low number of observations available, mostly due to a lack of available biosamples, prohibitive costs, or ethical reasons. Augmenting few real ...observations with generated in silico samples could lead to more robust analysis results and a higher reproducibility rate. Here, we propose the use of conditional single-cell generative adversarial neural networks (cscGAN) for the realistic generation of single-cell RNA-seq data. cscGAN learns non-linear gene-gene dependencies from complex, multiple cell type samples and uses this information to generate realistic cells of defined types. Augmenting sparse cell populations with cscGAN generated cells improves downstream analyses such as the detection of marker genes, the robustness and reliability of classifiers, the assessment of novel analysis algorithms, and might reduce the number of animal experiments and costs in consequence. cscGAN outperforms existing methods for single-cell RNA-seq data generation in quality and hold great promise for the realistic generation and augmentation of other biomedical data types.
Th17 cells are most abundant in the gut, where their presence depends on the intestinal microbiota. Here, we examined whether intestinal Th17 cells contribute to extra-intestinal Th17 responses in ...autoimmune kidney disease. We found high frequencies of Th17 cells in the kidneys of patients with antineutrophil cytoplasmatic antibody (ANCA)-associated glomerulonephritis. We utilized photoconversion of intestinal cells in Kaede mice to track intestinal T cell mobilization upon glomerulonephritis induction, and we found that Th17 cells egress from the gut in a S1P-receptor-1-dependent fashion and subsequently migrate to the kidney via the CCL20/CCR6 axis. Depletion of intestinal Th17 cells in germ-free and antibiotic-treated mice ameliorated renal disease, whereas expansion of these cells upon Citrobacter rodentium infection exacerbated pathology. Thus, in some autoimmune settings, intestinal Th17 cells migrate into target organs, where they contribute to pathology. Targeting the intestinal Th17 cell “reservoir” may present a therapeutic strategy for these autoimmune disorders.
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•Pathogenic TH17 cells migrate from the gut to the kidney in autoimmunity•TH17 cells egress the intestine in a S1PR1-dependent manner in glomerulonephritis•Targeting microbiota-induced TH17 cells ameliorates extraintestinal TH17 responses
By photolabelling intestinal cells, Krebs and colleagues provide direct evidence that microbiota-induced TH17 cells egress from the gut S1PR1-dependently and infiltrate the kidney via CCL20/CCR6 in immune-mediated diseases. This finding will build the basis for therapies targeting the intestinal TH17 cell “reservoir” to treat extraintestinal TH17 autoimmunity.
CD4
T cells are important drivers of tissue damage in immune-mediated renal diseases, such as anti-glomerular basement membrane glomerulonephritis, anti-neutrophil cytoplasmic antibody-associated ...glomerulonephritis, and lupus nephritis. The discovery of a distinct, IL-17-producing CD4
T-cell lineage termed T helper type 17 (T
17) cells has markedly advanced current understanding of the pathogenic mechanisms of organ-specific immunity and the pathways that lead to target organ damage. T
17 cells are characterized by the expression of the transcription factor RORγt, the production of the pro-inflammatory cytokines IL-17A, IL-17F, IL-22, and high expression of the chemokine receptor C-C-motif chemokine receptor 6 (CCR6). An emerging body of evidence from experimental models and human studies supports a key role for these cells in the development of renal damage, and has led to the identification of targets to inhibit the production of T
17 cells in the intestine, their migration, or their actions within the kidney. Here, we describe the identification, regulation, and function of T
17 cells and their associated pathways in immune-mediated kidney diseases, with a particular focus on the mechanisms underlying renal tissue injury. We also discuss the rationale for the translation of these findings into new therapeutic approaches in patients with autoimmune kidney disease.
Staphylococcus aureus is frequently detected in patients with sepsis and thus represents a major health burden worldwide. CD4+ T helper cells are involved in the immune response to S. aureus by ...supporting antibody production and phagocytosis. In particular, Th1 and Th17 cells secreting IFN-γ and IL-17A, are involved in the control of systemic S. aureus infections in humans and mice. To investigate the role of T cells in severe S. aureus infections, we established a mouse sepsis model in which the kidney was identified to be the organ with the highest bacterial load and abundance of Th17 cells. In this model, IL-17A but not IFN-γ was required for bacterial control. Using Il17aCre × R26YFP mice we could show that Th17 fate cells produce Th17 and Th1 cytokines, indicating a high degree of Th17 cell plasticity. Single cell RNA-sequencing of renal Th17 fate cells uncovered their heterogeneity and identified a cluster with a Th1 expression profile within the Th17 cell population, which was absent in mice with T-bet/Tbx21-deficiency in Th17 cells (Il17aCre x R26eYFP x Tbx21-flox). Blocking Th17 to Th1 transdifferentiation in Th17 fate cells in these mice resulted in increased S. aureus tissue loads. In summary, we highlight the impact of Th17 cells in controlling systemic S. aureus infections and show that T-bet expression by Th17 cells is required for bacterial clearance. While targeting the Th17 cell immune response is an important therapeutic option in autoimmunity, silencing Th17 cells might have detrimental effects in bacterial infections.
T cell plasticity in renal autoimmune disease Soukou, Shiwa; Huber, Samuel; Krebs, Christian F.
Cell & tissue research/Cell and tissue research,
08/2021, Letnik:
385, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The presence of immune cells is a morphological hallmark of rapidly progressive glomerulonephritis, a disease group that includes anti-glomerular basement membrane glomerulonephritis, lupus ...nephritis, and anti-neutrophil cytoplasmic antibody (ANCA)–associated glomerulonephritis. The cellular infiltrates include cells from both the innate and the adaptive immune responses. The latter includes CD4
+
and CD8
+
T cells. In the past, CD4
+
T cell subsets were viewed as terminally differentiated lineages with limited flexibility. However, it is now clear that Th17 cells can in fact have a high degree of plasticity and convert, for example, into pro-inflammatory Th1 cells or anti-inflammatory Tr1 cells. Interestingly, Th17 cells in experimental GN display limited spontaneous plasticity. Here we review the literature of CD4
+
T cell plasticity focusing on immune-mediated kidney disease. We point out the key findings of the past decade, in particular that targeting pathogenic Th17 cells by anti-CD3 injection can be a tool to modulate the CD4
+
T cell response. This anti-CD3 treatment can trigger a regulatory phenotype in Th17 cells and transdifferentiation of Th17 cells into immunosuppressive IL-10-expressing Tr1 cells (Tr1exTh17 cells). Thus, targeting Th17 cell plasticity could be envisaged as a new therapeutic approach in patients with glomerulonephritis.
IL-10 is essential to maintain intestinal homeostasis. CD4
T regulatory type 1 (T
1) cells produce large amounts of this cytokine and are therefore currently being examined in clinical trials as T ...cell therapy in patients with inflammatory bowel disease. However, factors and molecular signals sustaining T
1 cell regulatory activity still need to be identified to optimize the efficiency and ensure the safety of these trials. We investigated the role of IL-10 signaling in mature T
1 cells in vivo. Double IL-10
Foxp3
reporter mice and transgenic mice with impairment in IL-10 receptor signaling were used to test the activity of T
1 cells in a murine inflammatory bowel disease model, a model that resembles the trials performed in humans. The molecular signaling was elucidated in vitro. Finally, we used human T
1 cells, currently employed for cell therapy, to confirm our results. We found that murine T
1 cells expressed functional IL-10Rα. T
1 cells with impaired IL-10 receptor signaling lost their regulatory activity in vivo. T
1 cells required IL-10 receptor signaling to activate p38 MAPK, thereby sustaining IL-10 production, which ultimately mediated their suppressive activity. Finally, we confirmed these data using human T
1 cells. In conclusion, T
1 cell regulatory activity is dependent on IL-10 receptor signaling. These data suggest that to optimize T
1 cell-based therapy, IL-10 receptor expression has to be taken into consideration.
Single-cell biology is transforming the ability of researchers to understand cellular signaling and identity across medical and biological disciplines. Especially for immune-mediated diseases, a ...single-cell look at immune cell subtypes, signaling, and activity might yield fundamental insights into the disease etiology, mechanisms, and potential therapeutic interventions. In this review, we highlight recent advances in the field of single-cell RNA profiling and their application to understand renal function in health and disease. With a focus on the immune system, in particular on T cells, we propose some key directions of understanding renal inflammation using single-cell approaches. We detail the benefits and shortcomings of the various technological approaches outlined and give advice on potential pitfalls and challenges in experimental setup and computational analysis. Finally, we conclude with a brief outlook into a promising future for single-cell technologies to elucidate kidney function.
Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by biliary inflammation and fibrosis. We showed an elevated interferon γ response in patients with primary ...sclerosing cholangitis and in multidrug resistance protein 2-deficient ( Mdr2-/- ) mice developing sclerosing cholangitis. Interferon γ induced expression of the cytotoxic molecules granzyme B (GzmB) and TRAIL in hepatic lymphocytes and mediated liver fibrosis in sclerosing cholangitis.
In patient samples and Mdr2-/- mice, we identified lymphocyte clusters with a cytotoxic gene expression profile using single-cell RNA-seq and cellular indexing of transcriptomes and epitopes by sequencing analyses combined with multi-parameter flow cytometry. CD8 + T cells and NK cells showed increased expression of GzmB and TRAIL in sclerosing cholangitis. Depletion of CD8 + T cells ameliorated disease severity in Mdr2-/- mice. By using Mdr2-/- × Gzmb-/- and Mdr2-/- × Tnfsf10-/- mice, we investigated the significance of GzmB and TRAIL for disease progression in sclerosing cholangitis. Interestingly, the lack of GzmB resulted in reduced cholangiocyte apoptosis, liver injury, and fibrosis. In contrast, sclerosing cholangitis was aggravated in the absence of TRAIL. This correlated with elevated GzmB and interferon γ expression by CD8 + T cells and NK cells enhanced T-cell survival, and increased apoptosis and expansion of cholangiocytes.
GzmB induces apoptosis and fibrosis in sclerosing cholangitis, whereas TRAIL regulates inflammatory and cytotoxic immune responses, subsequently leading to reduced liver injury and fibrosis.
Immune-mediated kidney diseases are a leading cause of end-stage renal disease. Despite recent discoveries, the immunopathogenesis of this heterogeneous disease group remains incompletely understood, ...which is a major reason for the lack of specific therapies and targeted interventions. Accumulating evidence suggests that cytokines related to the T cell response play an important role in renal autoimmunity. In this issue of the JCI, Li et al. demonstrate that IL-23 directly regulates the metabolism of parenchymal kidney cells, thereby generating a proinflammatory microenvironment that exacerbates T cell-driven renal tissue damage. These findings identify the IL- 23/IL-17 axis as a key mediator of renal tissue injury and open new avenues for the development of pathogenesis-based treatment strategies in renal inflammatory diseases.
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