Biology subjects

Johansen, J.

Publications and source records attributed to Johansen, J..

8 recordsLinked to original sources

bioRxiv2026

Plasma proteomics identifies an IL-6–associated SAA axis linked to muscle wasting in patients with cancer cachexia

Nearly half of patients with advanced lung cancer develop cachexia, a debilitating syndrome that worsens prognosis. We conducted longitudinal clinical and plasma proteomic profiling of 67 patients with non-small cell lung cancer, with and without cachexia, during first-line treatment. Patients with cachexia at diagnosis exhibited elevated risk of hospitalization and treatment-delaying toxicity. At diagnosis, 128 plasma proteins were upregulated and 67 downregulated in cachectic relative to non-cachectic patients. Longitudinal assessments of body composition, physical performance, metabolism, clinical outcomes, and nutritional risk revealed distinct fat and muscle wasting phenotype trajectories. 71 proteins were associated with fat loss, 92 with muscle loss, and 177 with concurrent muscle and weight loss. We identified and functionally validated 8 plasma proteins linked to muscle loss and adverse clinical outcomes. In a separate cohort of 147 patients with advanced pancreatic cancer receiving the interleukin-6 (IL-6) inhibitor tocilizumab, pharmacological suppression of serum amyloid A (SAA) levels following IL-6 inhibition suggests a systemic IL-6-SAA axis. These results collectively highlight SAA1 and SAA2 as IL-6-driven, cachexia-associated factors that reduce human myotube width. These findings uncover new potential therapeutic targets for cachexia.

Systems Biology↗

bioRxiv2025

Unraveling the diversity and functional potential of cyanosphere microbiomes assembled from terrestrial cyanobacteria

The cyanosphere consists of heterotrophic microorganisms residing within the exopolysaccharide sheath of cyanobacteria, acting as a crucial interface between the cyanobacteria and their surrounding environment. Understanding the interactions between cyanobacteria and their cyanospheres is essential for predicting the success of terrestrial cyanobacteria in providing ecosystem services in nutrient-poor environments. However, knowledge of the microbial diversity within the cyanosphere remains limited. In this study, we employed metagenomic sequencing to reconstruct 410 metagenome-assembled genomes (MAGs) from cyanosphere-associated microbes linked to 56 unialgal terrestrial cyanobacteria cultures, representing 12 distinct cyanobacteria orders. Our findings revealed that the composition of cyanosphere microbial communities was unique to each cyanobacterial host and was significantly shaped by environmental factors such as habitat, precipitation, and temperature from which the cultures were originally obtained. Notably, three microbial genera, Brevundimonas, Devosia, and Sphingopyxis, were present in over 30% of the cyanospheres, forming a core cyanosphere microbiome. Functional gene analysis showed a distinction between the cyanobacteria and their associated cyanospheres, with dissimilatory nitrate reduction being the dominant pathway in the cyanosphere, while nitrogen fixation was more common in the cyanobacteria. Three cyanospheres also contained nitrogen fixation genes of which two hosts were nitrogen fixation capable themselves. The cyanosphere harbored genes for polysaccharide lyases, indicating a possible link to the exopolysaccharides produced by the cyanobacteria. Given the observed variability in microbial community composition and function across different cyanobacterial hosts, future ecological assessments and restoration efforts involving cyanobacteria should not only focus on the cyanobacteria themselves but also consider their associated microbial communities. ImportanceOur study identifies members of a highly understudied, and potentially under-valued, microbial community -- the cyanosphere. We used a diversity of terrestrial cyanobacteria to understand how the cyanosphere composition and predicted functions were influenced by the host cyanobacterium and environmental factors using metagenomics. This is a new approach to study the cyanosphere and provides insights into the diversity of terrestrial microbial communities. Importantly, our results underscore the need to consider microbial consortia when assessing the ecological potential of cyanobacteria in terrestrial restoration.

ecology↗

bioRxiv2024

CHAMP delivers accurate taxonomic profiles of the prokaryotes, eukaryotes, and bacteriophages in the human microbiome

Accurate taxonomic profiling of the human microbiome composition is crucial for linking microbial species to health outcomes. Therefore, we created the Clinical Microbiomics Human Microbiome Profiler (CHAMP), a comprehensive tool designed for the profiling of prokaryotes, eukaryotes, and viruses across all body sites. Boasting a reference database derived from 30,382 human microbiome samples, CHAMP covers 6,567 prokaryotic and 244 eukaryotic species as well as 64,003 viruses. We used a diverse set of in silico metagenomes and DNA mock communities to benchmark CHAMP against the established profiling tools MetaPhlAn 4, Bracken 2, mOTUs 3, and Phanta. CHAMP demonstrated unparalleled species recall, F1 score, and significantly reduced false positives compared to all other tools benchmarked. Indeed, the false positive relative abundance (FPRA) for CHAMP was, on average, 50-fold lower than the second-best performing profiler. CHAMP also proved to be more robust than the other tools to low sequencing depths, highlighting its application for low biomass samples. Taken together, this establishes CHAMP as a best-in-class human microbiome profiler of prokaryotes, eukaryotes, and viruses in diverse and complex communities across low and high biomass samples. CHAMP profiling is offered as a service by Clinical Microbiomics A/S and available for a fee at https://cosmosidhub.com.

bioinformatics↗

bioRxiv2024

Exploring Pharmacogenetic Factors Influencing Hydroxyurea Response in Tanzanian Sickle Cell Disease Patients: A Genomic Medicine Approach.

Sickle cell disease (SCD) continues to pose a significant public health challenge, particularly in sub-Saharan Africa. Despite its discovery over a century ago, the progress in developing and accessing effective interventions has been notably restricted. Currently, hydroxyurea stands as the primary drug in widespread use, and has been associated with elevated levels of fetal hemoglobin (HbF) and enhanced clinical outcomes. Notably, a substantial proportion, up to 30%, of patients do not exhibit a positive response to hydroxyurea treatment. There is compelling evidence suggesting that genetic factors play a crucial role in influencing the effectiveness of hydroxyurea. In this study, we present findings on the investigation of genetic variants influencing hydroxyurea response in 13 genetic loci associated with HbF synthesis and hydroxyurea drug metabolism focusing on MYB, HBB, HBG1, HBG2, BCL11A, KLF10, HAO2, NOS1, ARG2, SAR1A, CYP2C9, CYP2E1. We report remarkable genetic associations with CYP2C9, CYP2E1, KLF10, BCL11A, ARG2, HBG1, SAR1A, MYB, and NOS1 loci with hydroxyurea response. We also highlight associated pathways enrichment and gene-gene interactions analysis in the context of hydroxyurea treatment response.

genomics↗

bioRxiv2024

Prefrontal encoding of an internal model for emotional inference

A key function of brain systems mediating emotion is to learn to anticipate unpleasant experiences based on predictive sensory cues in the environment. While organisms readily associate sensory stimuli with aversive outcomes, higher-order forms of emotional learning and memory require inference to extrapolate the circumstances surrounding directly experienced aversive events to other indirectly related contexts and sensory patterns which werent a part of the original experience. To achieve this type of learning requires internal models of emotion which flexibly track directly experienced and inferred aversive associations. While the brain mechanisms of simple forms of aversive learning have been well studied in areas such as the amygdala, whether and how the brain represents internal models of emotionally relevant associations is not known. Here we report that neurons in the rodent dorsomedial prefrontal cortex (dmPFC) encode an internal model of emotion by linking sensory stimuli in the environment with aversive events, whether they were directly or indirectly associated with that experience. These representations are flexible, and updating the behavioral significance of individual features of the association selectively modifies corresponding dmPFC representations. While dmPFC population activity encodes all salient associations, dmPFC neurons projecting to the amygdala specifically represent and are required to express inferred associations. Together, these findings reveal how internal models of emotion are encoded in dmPFC to regulate subcortical systems for recall of inferred emotional memories.

neuroscience↗

bioRxiv2023

Adversarial and variational autoencoders improve metagenomic binning

Assembly of reads from metagenomic samples is a hard problem, often resulting in highly fragmented genome assemblies. Metagenomic binning allows us to reconstruct genomes by regrouping the sequences by their organism of origin, thus representing a crucial processing step when exploring the biological diversity of metagenomic samples. Here we present Adversarial Autoencoders for Metagenomics Binning (AAMB), an ensemble deep learning approach that integrates sequence co-abundances and tetranucleotide frequencies into a common denoised space that enables precise clustering of sequences into microbial genomes. When benchmarked, AAMB presented similar or better results compared with the state-of-the-art reference-free binner VAMB, reconstructing [~]7% more near-complete (NC) genomes across simulated and real data. In addition, genomes reconstructed using AAMB had higher completeness and greater taxonomic diversity compared with VAMB. Finally, we implemented a pipeline integrating VAMB and AAMB that enabled improved binning, recovering 20% and 29% more simulated and real NC genomes, respectively, compared to VAMB with moderate additional runtime. AAMB is freely available at https://github.com/RasmussenLab/VAMB.

bioinformatics↗

bioRxiv2021

Genome binning of viral entities from bulk metagenomics data

Despite the accelerating number of uncultivated virus sequences discovered in metagenomics and their apparent importance for health and disease, the human gut virome and its interactions with bacteria in the gastrointestinal are not well understood. In addition, a paucity of whole-virome datasets from subjects with gastrointestinal diseases is preventing a deeper understanding of the viromes role in disease and in gastrointestinal ecology as a whole. By combining a deep-learning based metagenomics binning algorithm with paired metagenome and metavirome datasets we developed the Phages from Metagenomics Binning (PHAMB) approach for binning thousands of viral genomes directly from bulk metagenomics data. Simultaneously our methodology enables clustering of viral genomes into accurate taxonomic viral populations. We applied this methodology on the Human Microbiome Project 2 (HMP2) cohort and recovered 6,077 HQ genomes from 1,024 viral populations and explored viral-host interactions. We show that binning can be advantageously applied to existing and future metagenomes to illuminate viral ecological dynamics with other microbiome constituents.

genomics↗

bioRxiv2019

JASPer controls interphase histone H3S10 phosphorylation by chromosomal kinase JIL-1 in Drosophila

In flies, the chromosomal kinase JIL-1 is responsible for most interphase histone H3S10 phosphorylation and has been proposed to protect active chromatin from acquiring heterochromatic marks, like dimethylated histone H3K9 (H3K9me2) and HP1. Here, we show that JIL-1s targeting to chromatin depends on a new PWWP domain-containing protein JASPer (JIL-1 Anchoring and Stabilizing Protein). The JASPer-JIL-1 (JJ)-complex is the major form of the kinase in vivo and is targeted to active genes and telomeric transposons via binding of the PWWP domain of JASPer to H3K36me3 nucleosomes. Put in place, the complex modulates the transcriptional output. JIL-1 and JJ-complex depletion in cycling cells lead to small changes in H3K9me2 distribution at active genes and telomeric transposons. Finally, we identified many new interactors of the endogenous JJ-complex and propose that JIL-1 not only prevents heterochromatin formation, but also coordinates chromatin-based regulation in the transcribed part of the genome.

molecular biology↗