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Missense-depleted regions in population exomes implicate ras superfamily nucleotide-binding protein alteration in patients with brain malformation.

Group B <i>Streptococcus</i> (GBS) is a leading cause of neonatal morbidity and mortality, and the primary source of exposure is the maternal vagina. Intrapartum antibiotic prophylaxis for GBS-positive mothers has reduced the incidence of GBS early-onset disease, however, potential long-lasting influence of an antibiotic-altered neonatal microbiota, and the frequent clinical sequelae in survivors of invasive GBS infection, compels alternative treatment options for GBS. Here, we examined the role of transcription factor hypoxia-inducible factor 1 alpha (HIF-1α), widely recognized as a regulator of immune activation during infection, in the host response to GBS. Given the importance of endogenous HIF-1α for innate immune defense, and the potential utility of HIF-1α stabilization in promoting bacterial clearance, we hypothesized that HIF-1α could play an important role in coordinating host responses to GBS in colonization and systemic disease. Counter to our hypothesis, we found that GBS infection did not induce HIF-1α expression in vaginal epithelial cells or murine macrophages, nor did HIF-1α deficiency alter GBS colonization or pathogenesis in vivo. Furthermore, pharmacological enhancement of HIF-1α did not improve control of GBS in pathogenesis and colonization models, while displaying inhibitory effects in vaginal epithelial cytokines and immune cell killing in vitro. Taken together, we conclude that HIF-1α is not a prominent aspect of the host response to GBS colonization or invasive disease, and its pharmacological modulation is unlikely to provide significant benefit against this important neonatal pathogen.

The gut microbiome modulates seizure susceptibility and the anti-seizure effects of the ketogenic diet (KD) in animal models, but whether these relationships translate to KD therapies for human drug-resistant epilepsy is unclear. Herein, we find that the clinical KD shifts the function of the gut microbiome in children with refractory epilepsy. Colonizing mice with KD-associated human gut microbes confers increased resistance to 6-Hz psychomotor seizures, as compared to colonization with gut microbes from matched pre-treatment controls. Parallel analysis of human donor and mouse recipient metagenomic and metabolomic profiles identifies subsets of shared functional features that are seen in response to KD treatment in humans and preserved upon transfer to mice fed a standard diet. These include enriched representation of microbial genes and metabolites related to anaplerosis, fatty acid beta-oxidation, and amino acid metabolism. Mice colonized with KD-associated human gut microbes further exhibit altered hippocampal and frontal cortical transcriptomic profiles relative to colonized pre-treatment controls, including differential expression of genes related to ATP synthesis, glutathione metabolism, oxidative phosphorylation, and translation. Integrative co-occurrence network analysis of the metagenomic, metabolomic, and brain transcriptomic datasets identifies features that are shared between human and mouse networks, and select microbial functional pathways and metabolites that are candidate primary drivers of hippocampal expression signatures related to epilepsy. Together, these findings reveal key microbial functions and biological pathways that are altered by clinical KD therapies for pediatric refractory epilepsy and further linked to microbiome-induced alterations in brain gene expression and seizure protection in mice.