Biology subjects

Hentschel, A.

Publications and source records attributed to Hentschel, A..

6 recordsLinked to original sources

bioRxiv2026

Vorinostat (SAHA) alters the skeletal muscle differentiation program

Epigenetic regulation, particularly histone acetylation, plays a critical role in skeletal muscle differentiation by modulating gene expression programs without altering DNA sequence. Histone deacetylases (HDACs) tightly regulate myogenesis by controlling the timing of differentiation. Pharmacological inhibition of HDACs has shown context-dependent effects on muscle cells. We investigated the effects of 1 {micro}M SAHA (suberoylanilide hydroxamic acid) on C2C12 and L6 myoblasts during differentiation using morphological, immunofluorescence, transcriptomic, and proteomic analyses. SAHA delayed early differentiation, reducing myotube formation with partial recovery at later stages. Transcriptomic analysis revealed time-dependent changes in pathways related to cytoskeleton, cell cycle, and chromatin regulation. Proteomics showed increased mitochondrial metabolism and reduced cytoskeletal components in C2C12 cells, while L6 cells displayed alterations in muscle structural and extracellular matrix proteins. SAHA induces stage- and model-dependent reprogramming of myogenesis, highlighting the importance of timing and cellular context in HDAC-targeted therapies.

cell biology↗

bioRxiv2026

SIMO - Single Section Integrative Multi-Omics - spatial mapping of metabolites and lipids combined with region-specific proteomics in a single tissue slice

Technological advances in biomedical sciences have accelerated multi-omics research, enabling high-resolution spatial mapping of diverse molecular compound classes. However, integrating spatial omics often requires serial tissue sections, limiting the alignment correlation across modalities. We present a single-section integrative multi-omics (SIMO) workflow that combines metabolite and lipid imaging with histopathology and region-specific proteomics. Using MALDI-MSI, tissue staining, and laser microdissection (LMD), SIMO delivers comprehensive metabolic, lipidomic, and proteomic insight from the same sample. Using mouse cardiac tissue we develop, control, and validate the methodology resulting in [~]60 imaged lipids and [~]60 imaged metabolites at 20 {micro}m pixel size and subsequently spatial proteomics by LMD, detecting over 5,000 proteins from the same tissue. To demonstrate the capabilities of the workflow in preclinical context, we apply SIMO to a metastasizing melanoma PDX model, identifying over 100 spatially localized lipids and metabolites, and over 5,000 proteins across metastases and non-tumor tissues in liver. SIMO enables precise ROI selection, statistical comparison of protein regulation, and alignment of metabolic and lipidomics pathways across spatial omics and region-specific proteomics, demonstrating its value as a spatial multi-omics platform.

biochemistry↗

bioRxiv2025

Acute AMPK activation does not adequately stimulate insulin signaling in skeletal muscle models of Myotonic Dystrophy Type 1

Myotonic Dystrophy Type 1 (DM1) is a multisystemic neuromuscular disorder characterized by skeletal muscle weakness, muscle atrophy, myotonia, cognitive impairments, gastrointestinal complications, and insulin resistance. While insulin resistance is well characterized in type 2 diabetes, its pathomechanism in DM1 remains unclear. Our study aims to elucidate the pathomechanism of insulin resistance in DM1 and how the pathway responds to AMPK stimulation. Proteomic analysis from sedentary wildtype and sedentary HSA-LR mice, a common DM1 mouse model, revealed downregulation of the AMPK-PGC-1 axis. Analysis of sedentary HSA-LR mice and exercised HSA-LR mice revealed activation of the AMPK-PGC-1 axis in exercised animals. To investigate this pathway, we treated WT and HSA-LR mice with the AMPK activator AICAR to examine the impact of AMPK stimulation on insulin signaling in DM1. This revealed impaired responses in the insulin pathway activation in the HSA-LR mice. Next, we examined whether these differences extended to a human model by treating control and DM1 myotubes with insulin and/or AICAR. In DM1 myotubes, both treatments produced dampened responses of key insulin signaling intermediates compared to controls. Taken together, these results suggest impaired activation of insulin signaling pathways in DM1 models and confirm the presence of insulin resistance with an impaired response to acute AMPK stimulation.

molecular biology↗

bioRxiv2024

The inhibitory effects of Remodelin on murine myoblasts differentiation

Myoblasts differentiation is a highly regulated and complex process leading to the formation of fused and aligned mature myotubes. Growing interest in the role of epigenetics in muscle differentiation has highlighted epi-modulators as crucial regulators of this process. Our in vitro study aimed to explore the potential effects of the inhibition of the acetyltransferase Nat10 on myoblasts differentiation, by using Remodelin, a Nat10 selective inhibitor. We cultivated and differentiated murine C2C12 myoblasts on ultra-compliant gelatin substrates for up to 16 days and treated them with Remodelin. A combination of morphological analyses, confocal microscopy, transcriptomic profiling (RNA-seq), quantitative proteomics and metabolomics analyses was employed to assess the impact of Nat10 inhibition on myotube formation and maturation. To evaluate the reproducibility of Remodelin effects across myogenic systems and species, L6 rat myoblasts were included as a secondary comparative model. Remodelin treatment impaired myotube organization, alignment, and structural maturation in both C2C12 and L6 cells compared to untreated controls. In C2C12 cultures, Remodelin also abolished spontaneous myotube contractility. Intersection of transcriptomics and proteomics analyses confirmed that Remodelin effectively slowed myotube formation. Overall, these results indicate that Remodelin broadly affects the regulatory networks involved in skeletal muscle differentiation.

cell biology↗

bioRxiv2024

Mitochondrial leakage and mtDNA damage trigger early immune response in Inclusion Body Myositis.

Polymyositis with mitochondrial pathology (PM-Mito) was first identified in 1997 as a subtype of idiopathic inflammatory myopathy. Recent findings demonstrated significant molecular similarities between PM-Mito and Inclusion Body Myositis (IBM), suggesting a trajectory from early to late IBM and prompting the inclusion of PM-Mito as an IBM precursor (early IBM) within the IBM spectrum. Both PM-Mito and IBM show mitochondrial abnormalities, suggesting mitochondrial disturbance is a critical element of IBM pathogenesis. The primary objective of this cross-sectional study was to characterize the mitochondrial phenotype in PM-Mito at histological, ultrastructural, and molecular levels and to study the interplay between mitochondrial dysfunction and inflammation. Skeletal muscle biopsies of 27 patients with PM-Mito and 27 with typical IBM were included for morphological and ultrastructural analysis. Mitochondrial DNA (mtDNA) copy number and deletions were assessed by qPCR and long-range PCR, respectively. In addition, full-length single-molecule sequencing of the mtDNA enabled precise mapping of deletions. Protein and RNA levels were studied using unbiased proteomic profiling, immunoblotting, and bulk RNA sequencing. Cell-free mtDNA (cfmtDNA) was measured in the serum of IBM patients. We found widespread mitochondrial abnormalities in both PM-Mito and IBM, illustrated by elevated numbers of COX-negative and SDH-positive fibers and prominent ultrastructural abnormalities with disorganized and concentric cristae within enlarged and dysmorphic mitochondria. MtDNA copy numbers were significantly reduced, and multiple large-scale mtDNA deletions were already evident in PM-Mito, compared to healthy age-matched controls, similar to the IBM group. The activation of the canonical cGAS/STING inflammatory pathway, possibly triggered by the intracellular leakage of mitochondrial DNA, was evident in PM-Mito and IBM. Elevated levels of circulating cfmtDNA also indicated leakage of mtDNA as a likely inflammatory trigger. In PM-Mito and IBM, these findings were accompanied by dysregulation of proteins and transcripts linked to the mitochondrial membranes. In summary, we identified that mitochondrial dysfunction with multiple mtDNA deletions and depletion, disturbed mitochondrial ultrastructure, and defects of the inner mitochondrial membrane are features of PM-Mito and IBM, underlining the concept of an IBM-spectrum disease (IBM-SD). The activation of inflammatory pathways related to mtDNA release indicates a significant role of mitochondria-associated inflammation in the pathogenesis of IBM-SD. Thus, mitochondrial abnormalities precede tissue remodeling and infiltration by specific T-cell subpopulations (e.g., KLRG1+) characteristic of late IBM. This study highlights the critical role of early mitochondrial abnormalities in the pathomechanism of IBM, which may lead to new approaches to therapy.

neuroscience↗

bioRxiv2021

ETV2 regulates PARP-1 binding protein to induce ER stress-mediated cell death in tuberin-deficient cells

Lymphangioleiomyomatosis (LAM) is a rare progressive disease, characterized by mutations in the tuberous sclerosis complex genes (Tsc1 or Tsc2), and hyperactivation of mechanistic target of rapamycin complex 1 (mTORC1). The effectiveness of mTORC1 inhibitors is limited by their lack of cytotoxic effects. Here, we report that E26 transformation specific (ETS) Variant Transcription Factor 2 (ETV2) is a critical regulator of Tsc2-deficient cell survival. Nuclear localization of ETV2 in Tsc2-deficient cells is mTORC1-independent and is enhanced by spleen tyrosine kinase (Syk) inhibition. In the nucleus, ETV2 transcriptionally regulates poly(ADP-ribose) polymerase 1 binding protein (PARPBP), a coregulator of transcription, mRNA and protein expression. Silencing of ETV2 or PARPBP in Tsc2-deficient cells induced ER-stress and increased cell death in vitro and in vivo. We also found ETV2 expression in human cells with loss of heterozygosity for TSC2 lending support to the translational relevance of our findings. In conclusion, we report a novel signaling axis unique to Syk-inhibition is mTORC1-independent and promotes a cytocidal response in Tsc2-deficient cells, and therefore, maybe a potential alternative therapeutic target in LAM.

cell biology↗