Biology subjects

Kremsner, P. G.

Publications and source records attributed to Kremsner, P. G..

3 recordsLinked to original sources

bioRxiv2025

Flagellin in the human gut microbiome is a diet-adjustable adjuvant for vaccination

The intestinal microbiota is thought to modulate immune responsiveness to vaccines. Human studies on this topic, however, have yielded inconsistent results1,2. We hypothesized that the microbiome would influence innate immune responses, and thus vaccine reactogenicity, more directly than vaccine immunogenicity. To test this, we established the {micro}HEAT (Microbial-Human Ecology And Temperature) study, which longitudinally profiled the fecal microbiota, oral body temperature and serum antibody responses of 171 healthy adults (18-40 years old) before and after vaccination for SARS-CoV-2. Increased temperature after vaccination ({Delta}T) was associated with habitual diet and with baseline metabolic and immune markers. The microbiomes of {Delta}T-high ({Delta}Thi) participants were characterized by high expression of flagellin and an overabundance of the flagellated bacterium Waltera. Fecal samples from {Delta}Thi participants induced more inflammation in human cells and stronger post-vaccine temperature responses in mice compared to {Delta}Tlo samples, suggesting a causal role for the microbiome. Moreover, Waltera flagellin replicated the inflammatory phenotypes in vitro and was modulable via a dietary additive. Overall, these data suggest that flagellin from the gut microbiome stimulates innate immunity and vaccine reactogenicity, and that this axis can be manipulated via diet. These findings have implications for improving human vaccine tolerance and immunogenicity.

microbiology↗

bioRxiv2025

Infection with gut parasites correlates with gut microbiome diversity across human populations in Africa

Soil-transmitted helminths (STH) are common in (sub)tropical regions and primarily affect impoverished populations. STHs reside in the gut, interacting both with the gut microbiota and host immunity. Clinical STH detection is laborious and often not performed within the context of gut microbiome studies. Here, we assessed whether fecal metagenome data could be used to assess STH infection, and to relate STH infection to microbiome diversity. We generated 310 gut metagenomes for mother-child pairs from two different locations in Gabon: one rural and one semi-urban. The presence and abundance of four STH parasites (Ascaris lumbricoides, Strongyloides stercoralis, Trichuris trichiura, and Necator americanus) were assessed using both microscopy and qPCR. Sequence data were used to characterize the microbiomes and to detect the presence of these four STH parasites. We found that metagenome data could accurately detect the presence of all four STHs, as reflected by high sensitivity and specificity compared to microscopy or qPCR detection. Furthermore, the number of STH species present in stool was associated with microbiome diversity and with the abundances of specific taxa, most notably in young children. We applied this approach to microbiome data from five other populations in Africa and corroborated our findings. Our results demonstrate that human intestinal parasites can be accurately detected via metagenomic sequencing, and highlight how infection with multiple STH parasites is linked to consistent features in the gut microbiome in populations in Africa.

microbiology↗

bioRxiv2019

A common polymorphism in the druggable ion channel PIEZO1 is associated with protection from severe malaria

Malaria caused by the Apicomplexan parasite Plasmodium falciparum has served as a strong evolutionary force throughout human history, selecting for red blood cell polymorphisms that confer innate protection against severe disease. Recently, gain-of-function mutations in the mechanosensitive ion channel PIEZO1 were shown to ameliorate Plasmodium parasite growth, blood-brain barrier dysfunction, and mortality in a mouse model of malaria. In humans, the gain-of-function allele PIEZO1 E756del is highly prevalent and enriched in Africans, raising the possibility that it is under positive selection due to malaria. Here we used a case-control study design to test for an association between PIEZO1 E756del and malaria severity among children in Gabon. We found that the E756del variant is strongly associated with protection against severe malaria in heterozygotes, independent of the protection conferred by the sickle cell trait (hemoglobin AS). In vitro experiments using donor red blood cells failed to find an effect of E756del on parasite growth, suggesting this variant confers a mild channel defect and/or that its protective effect may be mediated by other tissue types in vivo. Nonetheless, we show that Yoda1, a small molecule agonist of PIEZO1, has potent antimalarial activity in both E756del and wild-type red blood cells. Our findings demonstrate that PIEZO1 is an important innate determinant of malaria susceptibility in humans and holds potential as druggable host target for malaria control.

microbiology↗