Taki, A. | bioRxiv Science

bioRxiv2023

Increased interhemispheric functional connectivity during non-dominant hand movement in right-handed subjects

Hand preference is one of the behavioral expressions of lateralization in the brain. Previous fMRI studies, using conventional task-based functional MRI (fMRI), investigated the lateralization of brain function, and several regions including the motor cortex, putamen, thalamus, and cerebellum were activated during the single-hand movement. However, lateralization of functional connectivity related to hand preference has not been investigated. Here, we used the generalized psychophysiological interaction (gPPI) approach to investigate the alteration of functional connectivity during single-hand movement from the resting state in right-hand subjects. The functional connectivity in interhemispheric motor-related regions including the supplementary motor area, putamen, precentral gyrus, and cerebellum was significantly increased during non-dominant hand movement, while functional connectivity was not increased during dominant hand movement. The general linear model (GLM) showed activation in the left supplementary motor area, left precentral gyrus, and right cerebellum during right hand movement and activation in the right supplementary motor area, right precentral gyrus, and left cerebellum during left hand movement. These results indicate that a combination of GLM and gPPI analysis can detect the lateralization of hand preference more clearly in right-handed subjects.

neuroscience↗

bioRxiv2020

Effect of structural stability on endolysosomal degradation and T-cell reactivity of major shrimp allergen tropomyosin

BackgroundTropomyosins are highly conserved proteins, an attribute that forms the molecular basis for their IgE antibody cross-reactivity. Despite structural similarities, their allergenicity varies greatly between ingested and inhaled invertebrate sources. In this study, we investigated the relationship between the structural stability of different tropomyosins, their endolysosomal degradation patterns and T-cell reactivity. MethodsWe investigated the differences between four tropomyosins - the major shrimp allergen Pen m 1 and the minor allergens Der p 10 (dust mite), Bla g 7 (cockroach) and Ani s 3 (fish parasite) - in terms of IgE binding, structural stability, endolysosomal degradation and subsequent peptide generation, and T-cell cross-reactivity in a BALB/c murine model. ResultsDespite their conserved primary structure and consequent IgE co-reactivity, the invertebrate tropomyosins displayed different protein stabilities. Pen m 1 and Ani s 3, but not Der p 10 and Bla g 7 elicited differential melting temperatures that were pH-dependent. Endolysosomal experiments demonstrated differential degradation, as a function of stability, generating different peptide repertoires. Pen m 1 T-cell clones, with specificity for sequences highly conserved in all four tropomyosins, did not proliferate with Der p 10, Bla g 7 and Ani s 3, indicating that these peptides were not naturally produced for other invertebrate tropomyosins. ConclusionsOur data suggest that, although invertebrate tropomyosins exhibit a high degree of IgE cross-reactivity due to conserved B-cell epitopes, they do not necessarily share identical cross-reactive T-cell epitopes. This is likely due to differential endolysosomal processing as a function of different structural stabilities.

immunology↗