Biology subjects

Wirtz, L.

Publications and source records attributed to Wirtz, L..

6 recordsLinked to original sources

bioRxiv2026

Repeated Neuromuscular Electrical Stimulation Protocol Disrupts Muscle-to-Brain Signaling in Rats

Objective. Neuromuscular electrical stimulation (NMES) is increasingly used to preserve or restore muscle function in patients unable to exercise, and acute NMES improves cognitive performance and increases hippocampal mature brain-derived neurotrophic factor (BDNF). However, the consequences of repeated sessions for muscle-to-brain signaling remain poorly understood. We examined whether seven consecutive days of quadriceps NMES would reproduce this acute response. Methods. Male Wistar rats received daily 30-min quadriceps NMES or SHAM sessions under isoflurane for seven consecutive days. Blood was collected immediately after the final session and 24 h later, when muscle and hippocampal tissues were also collected. An independent cohort underwent behavioral testing. Results. Repeated NMES increased serum creatine kinase activity and quadriceps fibrillar collagen deposition without altering muscle mass, myofiber size, or degeneration-regeneration markers. These changes were accompanied by low-grade systemic inflammation and corticosterone elevation persisting 24 h after the final session. In the hippocampus, NMES increased inflammatory cytokine expression, astrocytic and microglial markers, and glucocorticoid receptor phosphorylation. Mature BDNF, TrkB phosphorylation and ERK1/2 signaling decreased, whereas proBDNF, p75NTR and JNK signaling increased; Akt and mTOR phosphorylation were unchanged. Synaptophysin, GAP43 and PSD95 also decreased. NMES increased marble burying and forced-swim immobility, without detectable changes in locomotion, recognition memory, or neuronal profile density. Conclusions. Repeated daily NMES engaged a distinct, maladaptive mode of muscle-to-brain signaling rather than reproducing the benefits reported after acute stimulation. Stimulation parameters and recovery intervals that avoid this response need to be defined before repeated NMES can be recommended as an exercise substitute.

physiology↗

bioRxiv2025

Specific and redundant roles for Gli2 and Gli3 in establishing cell fate during hair follicle development

Ectodermal appendage formation requires hedgehog (HH) signal reception, its conduction through the primary cilium and activation of Gli transcription factors (TF). How HH signalling induces cell-type-specific responses through Gli TF in stem cells (SCs) and their cilia-dependence remain open questions. Here, we use conditional mouse mutants to genetically dissect the roles of Gli and cilia HH mediators in the skin epithelium. Upon Gli2 depletion, hair follicle (HF) morphogenesis is delayed whereas sebaceous gland (SG) formation is enhanced, suggesting a dual role for Gli2 during appendage formation. By controlling proliferation of SG SCs, Gli2 impacts on the number and size of individual SG lobes. Whereas ablation of Gli3 shows no detectable phenotypes, HF cell fate is blocked in Gli2/3 double knockouts. In addition, loss of cilia phenocopies the loss of Gli2 but not the Gli2/3 mutants. Our study reveals that Gli3 exerts activator and cilia-independent functions in the absence of Gli2. Bullet pointsO_LIEpidermal Gli2 and Gli3 together mediate Hedgehog signalling and are essential for proper appendage formation C_LIO_LIGli3 activator function compensates for the loss of Gli2 during HF morphogenesis C_LIO_LIGli2 controls HF stem cell sub-compartments and SG formation C_LIO_LICilia mediate epidermal Gli2 but not Gli3 signalling in the skin epithelium C_LI

cell biology↗

bioRxiv2023

Plant pathogenic fungi hijack phosphate starvation signaling with conserved enzymatic effectors

Phosphate availability modulates plant immune function and regulates interactions with beneficial, phosphate-providing, microbes. Here, we describe the hijacking of plant phosphate sensing by a family of Nudix hydrolase effectors from pathogenic Magnaporthe oryzae and Colletotrichum fungi. Structural and enzymatic analyses of the Nudix effector family demonstrate that they selectively hydrolyze inositol pyrophosphates, a molecule used by plants to monitor phosphate status and regulate starvation responses. In M. oryzae, gene deletion and complementation experiments reveal that the enzymatic activity of a Nudix effector significantly contributes to pathogen virulence. Further, we show that this conserved effector family induces phosphate starvation signaling in plants. Our study elucidates a molecular mechanism, utilized by multiple phytopathogenic fungi, that manipulates the highly conserved plant phosphate sensing pathway to exacerbate disease. One-Sentence SummaryA family of conserved enzyme effectors from pathogenic fungi manipulate plant phosphate sensing to promote infection.

plant biology↗

bioRxiv2022

The soybean rust pathogen Phakopsora pachyrhizi displays transposable element proliferation that correlates with broad host-range adaptation on legumes

Asian soybean rust, caused by Phakopsora pachyrhizi, is one of the worlds most economically damaging agricultural diseases. Despite P. pachyrhizis impact, the exceptional size and complexity of its genome prevented generation of an accurate genome assembly. We simultaneously sequenced three P. pachyrhizi genomes uncovering a genome up to 1.25 Gb comprising two haplotypes with a transposable element (TE) content of ~93%. The proliferation of TEs within the genome occurred in several bursts and correlates with the radiation and speciation of the legumes. We present data of clear de-repression of TEs that mirrors expression of virulence-related candidate effectors. We can see a unique expansion in amino acid metabolism for this fungus. Our data shows that TEs play a dominant role in P. pachyrhizis genome and have a key impact on various processes such as host range adaptation, stress responses and genetic plasticity of the genome.

microbiology↗

bioRxiv2021

Ex vivo infection of human skin with herpes simplex virus 1 reveals mechanical wounds as insufficient entry portals via the skin surface

Herpes simplex virus 1 (HSV-1) enters its human host via the skin or mucosa. The open question is how the virus invades this highly protective tissue in vivo to approach its receptors in the epidermis and initiate infection. Here, we performed ex vivo infection studies in human skin to investigate how susceptible the epidermis and dermis are to HSV-1 and whether wounding facilitates viral invasion. Upon ex vivo infection of complete skin, only sample edges demonstrated infected cells. After removal of the dermis, HSV-1 efficiently invaded the basal layer, and from there, gained access to suprabasal layers supporting a high susceptibility of the epidermis. In contrast, only single infected cells were detected in the papillary layer of the separated dermis. Interestingly, after wounding, nearly no infection of the epidermis was observed via the skin surface. However, if the wounding of the skin samples led to breaks through the dermis, HSV-1 infected mainly keratinocytes via the wounded dermis. The application of latex beads revealed only occasional entry via the wounded dermis, however, facilitated penetration via the wounded skin surface. Thus, we suggest that the wounded human skin surface allows particle penetration but still provides barriers that prevent HSV-1 invasion.

microbiology↗

bioRxiv2020

Colletotrichum spp. from soybean cause disease on lupin but can also induce plant growth-promoting effects

Protein crop plants such as soybean and lupin attract increasing attention because of their potential use as forage, green manure or for the production of oil and protein for human consumption. While soybean production only recently gained more importance in Germany and within the whole EU in frame of protein strategies, lupin production already is well established in Germany. The cultivation of lupins is impeded by the hemibiotrophic ascomycete Colletotrichum lupini, the causing agent of anthracnose disease. Worldwide, soybean is also a host for a variety of Colletotrichum species, but so far this seems not to be the case in Germany. Cross-virulence between lupin and soybean infecting isolates is a potential threat, especially taking into consideration the overlap of possible soybean and lupine growing areas in Germany. To address this question, we systematically investigated the interaction of different Colletotrichum species isolated from soybean in Brazil on actual German soybean and lupin plant cultivars. Conversely, we tested the interaction of a German field isolate of C. lupini with soybean. Under controlled conditions, Colletotrichum species from soybean and lupin were able to cross-infect the other host plant with varying degrees of virulence, thus underpinning the potential risk of increased anthracnose diseases in the future. Interestingly, we observed a pronounced plant growth-promoting effect for some host-pathogen combinations which might open the route to the use of beneficial biological agents in lupine and soybean production.

plant biology↗