Biology subjects

da Silva, N. A.

Publications and source records attributed to da Silva, N. A..

5 recordsLinked to original sources

bioRxiv2024

Neolithic introgression of IL23R-related protection against chronic inflammatory bowel diseases in modern Europeans

BackgroundThe hypomorphic variant rs11209026-A in the IL23R gene provides significant protection against immune-related diseases in Europeans, notably inflammatory bowel disease (IBD). Today, the A-allele occurs with an average frequency of 5% in Europe. MethodsThis study comprised 251 ancient genomes from Europe spanning over 14,000 years. In these samples, the investigation focused on admixture informed analyses and selection scans of rs11209026-A and its haplotypes. Findingsrs11209026-A was found at high frequencies in Anatolian Farmers (AF, 18%) where it was likely under weak positive selection. AF later introduced the allele into the ancient European gene-pool. Subsequent admixture caused its frequency to decrease and formed the current southwest-to-northeast allele frequency cline in Europe. The geographic distribution of rs11209026-A may influence the gradient in IBD incidence rates that are highest in northern and eastern Europe. InterpretationGiven the dramatic changes from hunting and gathering to agriculture during the Neolithic, AF might have been exposed to selective pressures from a pro-inflammatory lifestyle and diet. Therefore, the protective A-allele may have increased survival by reducing intestinal inflammation and microbiome dysbiosis. The adaptively evolved function of the variant likely contributes to the high efficacy and low side-effects of modern IL-23 neutralization therapies for chronic inflammatory diseases. This study highlights how evolutionary informed research can provide promising targets for new therapeutic strategies. FundingDeutsche Forschungsgemeinschaft (DFG German Research Foundation) under Germanys Excellence Strategy - EXC 2167 390884018 and EXC 2150 390870439.

evolutionary biology↗

bioRxiv2024

Multilevel clinical fingerprinting: uncovering longitudinal changes in the functional connectome of the brain along the migraine cycle

Migraine is a common neurological disorder characterized by recurrent headache episodes alternating with symptom-free periods, which has been associated with alterations across large-scale functional brain networks albeit with variable findings. Critically, despite the cyclic nature of the disorder, longitudinal studies spanning the various phases of the migraine cycle are scarce. Here, we leverage the identifiability of individual functional connectomes (FC) to investigate changes along the migraine cycle. For this purpose, we employ a case-control longitudinal design to study a group of 10 patients with episodic menstrual or menstrual-related migraine without aura, in the 4 phases of their spontaneous migraine cycle (preictal, ictal, postictal, interictal), and a group of 14 healthy controls in corresponding phases of the menstrual cycle, using resting-state fMRI. We propose a novel multilevel clinical fingerprinting approach to analyse the differential FC identifiability within-subject, as well as within-session and within-group. The individual FC matrices are then reconstructed with 19 principal components maximizing identifiability at all levels, and analyzed with Network-Based Statistic to identify significant changes in FC strength. We observe decreased FC identifiability for patients in the preictal phase relative to controls, which increases with the progression of the attack and becomes comparable to controls in the interictal phase. Regarding the FC strength, is increased in the ictal and postictal phases relative to controls across several networks. Our novel multilevel clinical fingerprinting approach captures FC variations along the migraine cycle in a case-control longitudinal study, bringing new insights into the cyclic nature of the disorder.

bioengineering↗

bioRxiv2024

Structural connectome changes in episodic migraine: the role of the cerebellum

BackgroundThe pathophysiology of migraine remains poorly understood, yet a growing number of studies have shown structural connectivity disruptions across large-scale brain networks. Although both structural and functional changes have been found in the cerebellum of migraine patients, the cerebellum has barely been assessed in previous structural connectivity studies of migraine. Our objective is to investigate the structural connectivity of the entire brain, including the cerebellum, in individuals diagnosed with episodic migraine without aura during the interictal phase, compared with healthy controls. MethodsTo that end, 14 migraine patients and 15 healthy controls were recruited (all female), and diffusion-weighted and T1-weighted MRI data were acquired. The structural connectome was estimated for each participant based on two different whole-brain parcellations, including cortical and subcortical regions as well as the cerebellum. The structural connectivity patterns, as well as global and local graph theory metrics, were compared between patients and controls, for each of the two parcellations, using network-based statistics and a generalized linear model (GLM), respectively. We also compared the number of connectome streamlines within specific white matter tracts using a GLM. ResultsWe found increased structural connectivity in migraine patients relative to healthy controls with a distinct involvement of cerebellar regions, using both parcellations. Specifically, the node degree of the posterior lobe of the cerebellum was greater in patients than in controls and patients presented a higher number of streamlines within the anterior limb of the internal capsule. Moreover, the connectomes of patients exhibited greater global efficiency and shorter characteristic path length, which correlated with the age onset of migraine. ConclusionsA distinctive pattern of heightened structural connectivity and enhanced global efficiency in migraine patients compared to controls was identified, which distinctively involves the cerebellum. These findings provide evidence for increased integration within structural brain networks in migraine and underscore the significance of the cerebellum in migraine pathophysiology.

bioengineering↗

bioRxiv2023

Dietary 14C reservoir effects and the chronology of prehistoric burials at Sakhtysh, central European Russia

We present the first robust radiocarbon (14C) chronology for prehistoric burial activity at Sakhtysh, in European Russia, where nearly 180 inhumations attributed to Lyalovo and Volosovo pottery-using hunter-gatherer-fishers represent the largest known mortuary populations of these groups. Past attempts at 14C dating were restricted by poor preservation and limited understanding of diet and dietary 14C reservoir effects (DREs). We obtained 32 new AMS (Accelerator Mass Spectrometry) 14C dates on human petrous bones. Dietary stable isotopes ({delta}13C, {delta}15N) for all AMS-dated human samples allow us to propose a novel DRE correction model, using differences in 14C, {delta}13C and {delta}15N from bones and teeth of the same individuals to predict DREs of up to c.900 14C years. Our chronological model for 40 individuals dates Lyalovo burials to the early 5th millennium cal BC, and Volosovo burials to the mid-4th to early 3rd millennium. It reveals a previously unrecognised shift in the Volosovo subsistence economy at c.3300 cal BC, coinciding with a reorientation of trade networks, and shows that the last burial at Sakhtysh was the only one in a crouched position, which coincided with the beginning of Fatyanovo practices, the regional expression of the Yamnaya/Corded Ware expansion.

ecology↗

bioRxiv2023

Admixture as a source for HLA variation in Neolithic European farming communities

The northern European Neolithic is characterized by two major demographic events: immigration of early farmers (EF) from Anatolia (5500 BCE) and their admixture (from [~]4200 BCE) with western hunter-gatherers (WHG) forming late farmers (LF). The influence of this admixture event on variation in the immune-relevant human leukocyte antigen (HLA) region is understudied. Here, we conducted population and immunogenetic analyses on 83 individuals from six EF and LF sites located in present-day Germany. We observed significant shifts in HLA allele frequencies from EF to LF. The HLA diversity increased from EF to LF, likely due to admixture with WHG. However, it was considerably lower than in modern populations. Both EF and LF exhibited a relatively narrow HLA allele spectrum compared to today. This coincides with sparse traces of pathogen DNA, potentially indicating a lower pathogen pressure at the time. We additionally noted that LF resulted from sex-biased admixture from male WHG. TEASERMore restricted HLA allele spectrum and lower diversity in Neolithic farmers than in modern populations

genetics↗