Biology subjects

Roeth, R.

Publications and source records attributed to Roeth, R..

3 recordsLinked to original sources

bioRxiv2025

KCNQ1 regulates human neuronal development through mitochondrial and insulin signalling pathways

KCNQ1 encodes a voltage-gated potassium channel implicated in various peripheral and neurological disorders, yet its role during human neuronal development remains unclear. To investigate this, we generated KCNQ1 knockouts (KO) in human induced pluripotent stem cell lines and differentiated them into neural stem cells (NSCs) and cortical neurons. KCNQ1-deficient NSCs showed impaired neurite outgrowth, linked to reduced cell adhesion and disrupted neural cell adhesion molecule (NCAM) signalling. This phenotype was reproduced in wild-type and heterozygous lines by pharmacological KCNQ1 inhibition. Whole transcriptome, proteome, and follow-up analyses revealed mitochondrial dysfunction in KO NSCs, including reduced mitochondrial copy number and ATP synthase expression. Additionally, evidence was obtained for an impairment of insulin signalling in NSCs and neurons, with diminished insulin receptor gene expression and perturbation of key downstream signalling pathways (RAS-MAPK, PI3K-AKT). In neurons, KCNQ1 loss resulted in decreased synaptic activity and a more immature gene expression profile. Overall, our work reveals a novel role for KCNQ1 in human neurodevelopment by regulating cell adhesion, mitochondrial function, and insulin signalling. This work increases our understanding of KCNQ1 function in neurons and its contribution to neurological phenotypes observed in patients with KCNQ1-related diseases.

molecular biology↗

bioRxiv2020

Targeted Proteomics Reveals Quantitative Differences in Low Abundance Glycosyltransferases of Patients with Congenital Disorders of Glycosylation

Protein glycosylation is essential in all domains of life and its mutational impairment in humans can result in severe diseases named Congenital Disorders of Glycosylation (CDGs). Studies on molecular level are however challenging, because many glycosyltransferases in the endoplasmic reticulum (ER) are low abundance membrane proteins. We established a comprehensive multiple reaction monitoring (MRM) assay to quantify most human glycosyltransferases involved in the processes of N-glycosylation,O- and C-mannosylation in the ER. To increase reproducibility, a membrane protein fraction of isotopically labeled HEK 293T cells was used as an internal standard. With this internal standard the MRM assay is easily transferable between laboratories. 22 glycosyltransferases could be reliably quantified from whole cell lysates of HEK 293T cells, HeLa cells and skin fibroblast cell lines. We then analyzed fibroblasts derived from CDG type I patients with mutations in the ALG1,ALG2 or ALG11 gene. Mutations in ALG1 or ALG2 gene strongly reduced the levels of the ALG1 and ALG2 protein, respectively. In contrast, the levels of all other glycosyltransferases remained unchanged, which was unexpected given evidence that the ALG1, ALG2 and ALG11 proteins form a stable complex. This study describes an efficient workflow for the development of MRM assays for low abundance proteins, establishes a ready-to-use tool for the comprehensive quantification of ER-localized glycosyltransferases and provides new insight into the organization of disease-relevant glycosylation processes.

biochemistry↗

bioRxiv2020

Functional and molecular early enteric biomarkers for Parkinson's disease in mice and men

Parkinsons disease (PD) usually has a late clinical onset. The lack of early biomarkers for the disease represents a major challenge for developing timely treatment interventions. Here, we use an -synuclein-overexpressing transgenic (Th-1-SNCA-A30P) mouse model of PD to identify appropriate candidate markers in the gut for early stages of PD before hallmark symptoms begin to manifest. A30P mice did not show alterations in gait parameters at 2 months of age, and these mice were therefore defined as pre-symptomatic A30P mice (psA30P). We discovered early functional motility changes in the gut and early molecular dysregulations in the myenteric plexus of psA30P mice by comparative protein and miRNA profiling and cell culture experiments. We found that the proteins neurofilament light chain, vesicle-associated membrane protein 2 and calbindin 2, together with the miRNAs that regulate them, are potential biomarkers of early PD that may facilitate timely treatment and/or prevention of PD in men.

neuroscience↗