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Biology subjects

Hyoty, H.

Publications and source records attributed to Hyoty, H..

8 recordsLinked to original sources

Enterovirus-driven interferon signaling induces epithelial TG2 via JAK-STAT: Implications for the onset of celiac disease

Background & AimsCeliac disease (CeD) is an autoimmune disorder triggered by dietary gluten in genetically predisposed individuals, but environmental factors contributing to disease onset remain incompletely defined. Epidemiological studies implicate enterovirus infections as potential triggers. Here, we investigated the epithelial-intrinsic mechanisms by which coxsackievirus B1 (CVB1) infection may prime the intestine for CeD. MethodsHuman intestinal organoids were infected with CVB1 and analyzed using single-cell RNA sequencing to resolve lineage-specific responses. Interferon signaling and transglutaminase 2 (TG2) regulation were interrogated using type I interferon stimulation and pharmacologic JAK inhibition. ResultsCVB1 infection induced a robust epithelial antiviral program dominated by type I interferon signaling. This response was accompanied by marked upregulation of TG2 expression and enzymatic activity. Single-cell analysis localized TG2 induction to immature goblet-lineage cells, which exhibited strong interferon-stimulated gene activation and epithelial stress signatures. Mechanistically, IFN-/{beta} stimulation was sufficient to induce TG2 via JAK-STAT signaling, while JAK inhibition effectively suppressed both TG2 expression and activity. In parallel, CVB1 infection triggered coordinated mucin remodeling, including induction of MUC5AC, indicating interferon-linked epithelial reprogramming. Notably, these effects occurred independently of immune cell involvement, highlighting a cell-intrinsic pathway. ConclusionOur findings identify a direct epithelial mechanism linking enterovirus infection to TG2 activation via interferon-driven JAK-STAT signaling. This pathway provides a mechanistic bridge between viral infection and gluten peptide modification, a critical step in the onset of CeD. The reversibility of TG2 induction by JAK inhibition suggests a potential strategy to prevent virus-mediated priming of celiac disease.

immunology↗

Scinderin-driven Golgi Actin Remodeling coordinates GLP-1 and insulin secretion to regulate glucose homeostasis

Maintenance of glucose homeostasis requires coordinated hormone secretion from intestinal enteroendocrine cells and pancreatic {beta}-cells, yet the intracellular mechanisms that couple nutrient sensing to endocrine output remain poorly defined. Here, we identify the actin remodeler Scinderin (SCIN) as a shared regulator of hormone secretion across these systems. SCIN is selectively expressed in enteroendocrine L-cells and pancreatic {beta}-cells, where it localizes to phosphatidylinositol-4-phosphate (PI(4)P)-enriched Golgi membranes and controls Golgi-associated actin dynamics. Loss of SCIN disrupts Golgi organization, impairs prohormone trafficking, and reduces secretory granule formation, resulting in defective nutrient-stimulated GLP-1 and insulin secretion while preserving cAMP-dependent amplification pathways. In vivo, tissue-specific deletion of Scin compromises incretin responses, {beta}-cell insulin secretion, and systemic glucose homeostasis. Consistent with these findings, SCIN expression is reduced in human diabetic {beta}-cells and associates with stress-related loss of {beta}-cell maturity. Transcriptomic analyses reveal a conserved Golgi stress program upon SCIN loss, linking intracellular trafficking defects to endocrine dysfunction. Together, our results identify SCIN-dependent Golgi actin remodeling as a rate-limiting intracellular mechanism coordinating enteroendocrine and pancreatic hormone secretion. This work uncovers a shared, targetable node controlling endocrine output, providing a mechanistic link between secretory pathway dysfunction and diabetes.

cell biology↗

Production, analysis, and safety assessment of a soil and plant-based natural material with microbiome- and immune-modulatory effects

Reduced contact with the microbiota from the natural environment has been suggested to contribute to the rising incidence of immune-mediated inflammatory disorders (IMIDs) in the western, highly urbanized societies. In line with this, we have previously shown that exposure to environmental microbiota in the form of a blend comprising of soil and plant-based material (biodiversity blend; BDB) enhances the diversity of human commensal microflora and promotes immunoregulation that may be associated with a reduced risk for IMIDs. To provide a framework for future preclinical studies and clinical trials, this study describes how the preparation of BDB was standardized, its microbial content and safety assessments. Multiple batches of BDB were manufactured and microbial composition analyzed using 16S rRNA gene sequencing. We observed a consistently high alpha diversity and relative abundance of bacteria normally found in soil and vegetation. We also found that inactivation of BDB by autoclaving effectively inactivates human and murine bacteria, viruses and parasites. Finally, we demonstrate that experimental mice prone to develop IMIDs (non-obese diabetic, NOD, mouse model) can be exposed to BDB without causing adverse effects on animal health and welfare. Our study lays the foundation for a safe, sustainable, and affordable way to mimic exposure to natural microbiota that has the potential to have enormous health- and socio-economic impacts.

microbiology↗

Coxsackievirus infection induces direct pancreatic β-cell killing but poor anti-viral CD8+ T-cell responses

Coxsackievirus B (CVB) infection of pancreatic {beta} cells is associated with {beta}-cell autoimmunity. We investigated how CVB impacts human {beta} cells and anti-CVB T-cell responses. {beta} cells were efficiently infected by CVB in vitro, downregulated HLA Class I and presented few, selected HLA-bound viral peptides. Circulating CD8+ T cells from CVB-seropositive individuals recognized only a fraction of these peptides, and only another sub-fraction was targeted by effector/memory T cells that expressed the exhaustion marker PD-1. T cells recognizing a CVB epitope cross-reacted with the {beta}-cell antigen GAD. Infected {beta} cells, which formed filopodia to propagate infection, were more efficiently killed by CVB than by CVB-reactive T cells. Thus, our in-vitro and ex-vivo data highlight limited T-cell responses to CVB, supporting the rationale for CVB vaccination trials for type 1 diabetes prevention. CD8+ T cells recognizing structural and non-structural CVB epitopes provide biomarkers to differentially follow response to infection and vaccination.

immunology↗

Metabolic Alterations in Human Peripheral Blood Mononuclear Cells Associate with Progression to Islet Autoimmunity and Type 1 Diabetes

Previous metabolomics studies suggest that type 1 diabetes (T1D) is preceded by specific metabolic disturbances. Here we asked whether distinct metabolic patterns occur in peripheral blood mononuclear cells (PBMCs) of children later developing pancreatic {beta}-cell autoimmunity or overt T1D. In a longitudinal cohort setting, PBMC metabolomic analysis was applied in children who either (1) progressed to T1D (PT1D, n=34), (2) seroconverted to [≥]1 islet autoantibody without progressing to T1D (P1Ab, n=27), or (3) remained autoantibody negative during follow-up (CTRL, n=10). During the first year of life, levels of most lipids and polar metabolites were lower in PT1D and P1Ab, versus CTRLs. Pathway overrepresentation analysis suggested alanine, aspartate, glutamate, glycerophospholipid and sphingolipid metabolism were overrepresented in PT1D. Genome-scale metabolic models of PBMCs in T1D progression were developed using available transcriptomics data and constrained with metabolomics data from our study. Metabolic modeling confirmed altered ceramide pathways as specifically associated with T1D progression.

molecular biology↗

Circulating Metabolites in Progression to Islet Autoimmunity and Type 1 Diabetes

Previous studies suggest that metabolic dysregulation precedes the onset of type 1 diabetes (T1D). However, these metabolic disturbances and their specific role in disease initiation remain poorly understood. Here we analysed polar metabolites from 415 longitudinal plasma samples in a prospective cohort of children in three study groups: those who progressed to T1D (PT1D), who seroconverted to one islet autoantibody (Ab) but not to T1D (P1Ab), and Ab-negative controls (CTR). In early infancy, PT1D associated with downregulated amino acids, sugar derivatives and fatty acids, including catabolites of microbial origin, as compared to CTR. Methionine remained persistently upregulated in PT1D as compared to CTR and P1Ab. Appearance of islet autoantibodies associated with decreased glutamic and aspartic acids. Our findings suggest that children who progress to T1D have a unique metabolic profile, which is however altered with the onset of islet autoantibodies. Our findings may assist in early prediction of T1D.

biochemistry↗

Detection of enterovirus protein and RNA in multiple tissues from nPOD organ donors with type 1 diabetes

Epidemiological studies have shown an association between enterovirus (EV) infections and type 1 diabetes (T1D), and EV protein has been detected in the pancreatic islets of T1D patients. Here we correlated the detection of EVs in lymphoid tissues (spleen and pancreatic lymph nodes) and small intestinal mucosa to the virus detection in the pancreas of T1D, autoantibody-positive (aab+) and non-diabetic control organ donors of the Network for Pancreatic Organ Donors with Diabetes (nPOD) study. Formalin-fixed paraffin-embedded tissue samples were screened for insulin and EV protein using immunohistochemistry, and frozen tissue for EV genome using RT-PCR. The presence of EV protein in the pancreatic islets correlated with the presence of insulin-positive cells. Altogether 62 % of T1D and aab+ donors were positive for EV protein in pancreatic islets (only insulin-positive donors included), 40 % in duodenum and 32 % in spleen, compared to 33 %, 14 %, and 27 % of non-diabetic controls. Pancreatic lymph nodes were positive for EV protein in 60 % of T1D and aab+ cases. T1D and aab+ donors were more frequently VP1-positive in multiple organs than control donors (39 % vs. 11 %; including only insulin-positive donors). EV RNA was found in selected donors and from multiple tissue types except for duodenum, and individual T1D and aab+ donors were EV RNA-positive in multiple organs. The role of extra-pancreatic organs and their interplay with EV in T1D pathogenesis remains to be solved, but we hypothesize that these organs may serve as a reservoir for the virus which may reside in these tissues in a slow-replicating persistent form.

epidemiology↗

Dynamics of Plasma Lipidome in Progression to Islet Autoimmunity and Type 1 Diabetes: Type 1 Diabetes Prediction and Prevention Study (DIPP)

Type 1 diabetes (T1D) is one of the most prevalent autoimmune diseases among children in Western countries. Earlier metabolomics studies suggest that T1D is preceded by dysregulation of lipid metabolism. Here we used a lipidomics approach to analyze molecular lipids in a prospective series of 428 plasma samples from 40 children who progressed to T1D (PT1D), 40 children who developed at least a single islet autoantibody but did not progress to T1D during the follow-up (P1Ab) and 40 matched controls (CTR). Sphingomyelins were found to be persistently downregulated in PT1D when compared to the P1Ab and CTR groups. Triacylglycerols and phosphatidylcholines were mainly downregulated in PT1D as compared to P1Ab at the age of 3 months. Our study suggests that children who progressed to islet autoimmunity or overt T1D are characterized by distinct lipidomic signatures, which may be helpful in the identification of at-risk children before the initiation of autoimmunity.

biochemistry↗