Recent studies involving transplantation of feces from schizophrenia (SCZ) patients and their healthy controls into germ-free mice have demonstrated that the gut microbiome plays a critical role in mediating SCZ-linked physiology and behavior. To date, only one animal model (a metabotropic glutamate receptor 5 knockout) of SCZ has been reported to recapitulate SCZ-linked gut dysbiosis. Since human 22q11.2 microdeletion syndrome is associated with increased risk of SCZ, we investigated whether the 22q11.2 microdeletion (Q22) mouse model of SCZ exhibits both SCZ-linked behaviors and intestinal dysbiosis. We demonstrated that Q22 mice display increased acoustic startle response and ileal (but not colonic) dysbiosis, which may be due to the role of the ileum as an intestinal region with high immune and neuroimmune activity. We additionally identified a negative correlation between the abundance of a Streptococcus species in the ilea of Q22 mice and their acoustic startle response, providing early evidence of a gut-brain relationship in these mice. Given the translational relevance of this mouse model, our work suggests that Q22 mice could have considerable utility in preclinical research probing the relationship between gut dysbiosis and the gut-brain axis in the pathogenesis of SCZ.

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Exposures to a wide repertoire of common childhood infections and strong inflammatory responses to those infections are associated with the risk of pediatric B-cell acute lymphoblastic leukemia (B-ALL) in opposing directions. Neonatal inflammatory markers are also related to risk by unknown mechanism(s). Here, we demonstrate that interleukin-10 (IL-10) deficiency, which is associated with childhood B-ALL, indirectly impairs B lymphopoiesis and increases B-cell DNA damage in association with a module of 6 proinflammatory/myeloid-associated cytokines (IL-1α, IL-6, IL-12p40, IL-13, macrophage inflammatory protein-1β/CCL4, and granulocyte colony-stimulating factor). Importantly, antibiotics attenuated inflammation and B-cell defects in preleukemic Cdkn2a-/-Il10-/- mice. In an ETV6-RUNX1+ (E6R1+) Cdkn2a-/- mouse model of B-ALL, decreased levels of IL-10 accelerated B-cell neoplasms in a dose-dependent manner and altered the mutational profile of these neoplasms. Our results illuminate a mechanism through which a low level of IL-10 can create a risk for leukemic transformation and support developing evidence that microbial dysbiosis contributes to pediatric B-ALL.

BACKGROUND: The pathogenesis of Crohns disease involves genetic and environmental factors, with the gut microbiome playing a crucial role. The Crohns disease-associated variant rs13107325 in the SLC39A8 gene results in an A391T substitution in the ZIP8 metal ion transporter and has previously been linked to alterations in the colonic microbiome in variant carriers. We hypothesized that the A391T substitution alters metal ion homeostasis in the colonic mucosal-luminal interface, thereby inducing dysbiosis which may promote intestinal inflammation. METHODS: To evaluate this hypothesis, we generated a SLC39A8 A393T mouse model (matching human A391T). We first examined trace element abundance in the colonic mucosal epithelium and lumen of homozygous A393T and wild-type (WT) mice to determine if the variant affected metal distribution. We also performed 16S rRNA gene sequencing on colon samples at 2 months, 3-4 months, and 12 months of age, and conducted histological scoring of colon tissue collected from 5-month and 10-month old mice. RESULTS: Consistent with an effect of the variant on ZIP8 function, homozygous A393T mice exhibited increased cobalt in the colonic mucosa, but reduced iron, zinc, manganese, cobalt, copper, and cadmium in the colonic lumen. 16S rRNA gene sequencing of colon samples revealed variant-linked effects on microbiome beta diversity in 2-month-, 3-4-month-, and 12-month-old mice. Histological scoring showed spontaneous intestinal inflammation in 10-month but not in 5-month-old mice. Lastly, predicted pathway analysis of the microbiome samples revealed differential enrichment of iron-, zinc-, and cobalt-dependent pathways in A393T mice compared to wild-type controls. CONCLUSION: These results suggest that the variant in SLC39A8 primarily restricts metal availability to the microbiota, resulting in compositions that can adapt to the environment and that A393T-linked dysbiosis occurs prior to the onset of inflammation. This study paves the way for future studies investigating risk variants as microbiome-disease modifiers.