Biology subjects

Jahnen-Dechent, W.

Publications and source records attributed to Jahnen-Dechent, W..

6 recordsLinked to original sources

bioRxiv2026

Single-cell characterization of human periodontal ligament (PDL) cells reveals uniformly mesenchymal populations in matched maxilla and mandible pairs from four donors

The periodontal ligament (PDL) is a mechanically active connective tissue whose fibroblasts and resident progenitor cells drive tooth support, remodeling, and regeneration. Although PDL cell populations are known to be heterogeneous, the composition of expanded primary PDL cultures and the extent to which anatomical origin shapes their transcriptome remain incompletely defined. Here we applied single-cell RNA sequencing to cultured primary PDL cells isolated from matched upper (maxilla) and lower (mandible) jaw sites of four donors, yielding 43,423 cells that were integrated across donors and analyzed by unsupervised clustering. The expanded cultures were uniformly mesenchymal and fibroblastic, essentially devoid of endothelial and immune signatures, and resolved into ten functionally distinct fibroblast substates rather than discrete cell types, including proliferating, collagen- and extracellular-matrix-high, contractile, and progenitor-like populations. Donor identity was the dominant source of transcriptional variation, with several substates restricted to individual donors. A donor-controlled comparison of maxilla versus mandible revealed only a small set of differentially expressed genes, headed by craniofacial positional-identity transcription factors (PITX1 higher in the mandible; BARX1, ALX1, and NKX6-1 higher in the maxilla), indicating that cultured PDL cells retain embryonic positional memory. In contrast, curated wound-healing gene modules did not differ significantly between jaws, and the transcriptional data therefore did not support the clinical impression of faster healing in the maxilla, suggesting that the healing asymmetry more likely reflects vascular, mechanical, and inflammatory signaling factors acting beyond the steady-state transcriptome. These findings characterize the cellular composition of expanded PDL cultures and identify positional identity as the principal jaw-dependent transcriptional feature.

genomics↗

bioRxiv2025

Cell-based calcification assays - magnesium overrules calcium phosphate saturation in overall outcome

Soft tissue calcification, a common cause of cardiovascular mortality in conditions like chronic kidney disease (CKD), is influenced by magnesium (Mg). However, the exact mechanism, whether extracellular chemistry-mediated or cell-mediated, remains unclear. Here we focused on the extracellular milieu. Using fluorescence-labelled fetuin-A and a live imaging platform, we found that Mg reduced spontaneous mineral precipitation by stabilizing calcium and phosphate as colloidal protein-mineral particles (CPP) in calcification media containing up to 10 mM calcium and phosphate. Addition of 1.25-5 mM Mg progressively stabilized the protein-mineral particles in the fluid phase, increasing calcification. Dynamic light scattering revealed smaller and more numerous CPP at up to 4 mM Mg. At 10 mM Mg, no calcification occurred even with 10 mM added calcium and phosphate. This suggested a critical Mg concentration range in supersaturated calcification media, where Mg paradoxically enhanced calcification by stabilizing mineral precursors and increasing their availability. These findings demonstrate Mgs dual role: an inhibitor of protein-mineral complex aggregation at high concentrations and a facilitator of mineral availability from colloidal protein-mineral phases at concentrations up to about 5 mM Mg. This highlights the role of Mg in providing highly dynamic, mineral-rich, stable protein-mineral complexes driving matrix calcification, yet preventing mineral precipitation.

pathology↗

bioRxiv2025

Miniaturized Device for Assessing Calcification Propensity of Biohybrid Implants Under Continuous Flow

Biohybrid implants are a promising development for cardiovascular disease treatment but suffer from problems like thrombogenesis and calcification. However, testing and validating biohybrid implants can be difficult and expensive due to material handling, fabrication methods and specialty medium components. The devices used to test potential samples can be large and expensive, requiring significant amounts of cell culture medium to operate. Additional, conventional static cell culture conditions do not accurately represent the vascular environment as shear and mechanical forces play key roles in the development of calcification. To address these challenges, a miniaturized, dual-channel flow chamber was designed and validated that allowed for real-time visualization of biohybrid calcification in a physiological environment. Computational Fluid Dynamics simulations were performed to determine the flow characteristics that generated physiological shear stress homogeneously across the sample surface. Micro particle tracking velocimetry measurements validated the simulated shear stresses near the sample surface. Two implant materials used for biohybrid construction, bovine pericardium and polycarbonate urethane, were inserted in the device and exposed to a flowing calcification medium for 14 days. Fluorescent fetuin-A was introduced into the calcification medium for real-time calcification monitoring. The two materials were compared with matched samples calcified in a large fatigue tester for 14 days. Our results showed similar material calcification for bovine pericardium and no calcification for polycarbonate urethane in the large fatigue tester and in our newly developed device. Biohybrid textile-reinforced fibrin-based scaffold populated with vascular smooth muscle cells started to calcify over 7 days in calcification medium. We conclude that this platform will provide novel insights into the origin and progression of pathological calcification and its potentially harmful health effects, which can occur as a result of tissue or metabolic abnormalities, disease, or implantation of certain biomaterials, by providing the ability to monitor the progression of calcification in biohybrid implants in real time, while also minimizing the cost and size of samples and reagents required for testing.

bioengineering↗

bioRxiv2025

Two Transport Routes for Fetuin-A-based Mineral Complexes in Osteogenic Matrix Mineralization

Living organisms must transport calcium and phosphate at high concentrations to enable bone formation without triggering uncontrolled mineral precipitation. Fetuin-A binds calcium phosphate to form soluble calciprotein complexes, but how these complexes contribute to physiological mineralization has remained unclear. Here we show that Fetuin-A-based mineral complexes exist in functionally distinct states that determine mineral bioavailability. Using cryogenic and liquid-phase electron microscopy, biochemical analysis, and osteoblast cell cultures, we demonstrate that small, chemically labile calciprotein monomers directly mineralize collagen fibrils, whereas larger, chemically matured primary calciprotein particles cannot. Instead, these particles require cellular uptake and lysosomal processing to release mineral for matrix deposition. This functional divergence arises from a irreversible chemical transformation of the mineral phase that drives the primary CPP assembly. Together, our findings establish nanoscale chemical maturation as a key control point that separates mineral transport from mineralization, reframing our understanding both physiological bone formation and pathological calcification.

biochemistry↗

bioRxiv2019

Luminal Calcification of the Microvasculature in Fetuin-A Deficient Mice Leads to Premature Aging and Death

ObjectiveThe plasma protein fetuin-A mediates the formation of protein-mineral colloids known as calciprotein particles (CPP) - rapid clearance of these CPP by the reticuloendothelial system prevents errant mineral precipitation and therefore ectopic mineralization (calcification). The mutant mouse strain D2,Ahsg-/- combines fetuin-A deficiency with the mineralization-prone DBA/2 genetic background, having a particularly severe compound phenotype of microvascular and soft tissue mineralization. Here we studied mechanisms leading to soft tissue mineralization, organ damage and premature aging in these mice.\n\nApproach and ResultsWe analyzed mice longitudinally by echocardiography, X-ray-computed tomography, analytical electron microscopy, histology, mass spectrometry proteomics, and genome-wide microarray-based expression analyses of D2 wildtype and Ahsg-/- mice.\n\nFetuin-A deficient mice had calcified lesions in myocardium, lung, brown adipose tissue, reproductive organs, spleen, pancreas, kidney and the skin, associated with reduced growth, cardiac output and premature aging. Importantly, early stage calcified lesions presented in the lumen of the microvasculature suggesting precipitation of mineral containing complexes from the fluid phase of blood. Genome-wide expression analysis of calcified lesions and surrounding (not calcified) tissue, together with morphological observations, indicated that the ectopic mineralization was not associated with osteochondrogenic cell differentiation, but rather with thrombosis and fibrosis.\n\nConclusionsCollectively, these results demonstrate that pathological mineralization can start by intravascular mineral deposition causing microvasculopathy, which impacts on growth, organ function and survival. Our study underscores the importance of fetuin-A and related systemic regulators of mineralized matrix metabolism to prevent cardiovascular disease, especially in dysregulated mineral homeostasis.

physiology↗

bioRxiv2019

Soft tissue calcification in mice is governed by fetuin-A, pyrophosphate and magnesium

ObjectiveCalcifications can disrupt organ function in the cardiovascular system and the kidney, and are particularly common in patients with chronic kidney disease (CKD). Fetuin-A deficient mice maintained against the genetic background DBA/2 exhibit particularly severe soft tissue calcifications, while fetuin-A deficient C57BL/6 mice remain healthy. We employed molecular genetic analysis to identify risk factors of calcification in fetuin-A deficient mice. We sought to identify pharmaceutical therapeutic target that could be influenced by dietary of parenteral supplementation.\n\nApproach and ResultsWe studied the progeny of an intercross of fetuin-A deficient DBA/2 and C57BL/6 mice to identify candidate risk genes involved in calcification. We determined that a hypomorphic mutation of the Abcc6 gene, a liver ATP transporter supplying systemic pyrophosphate, and failure to regulate the TRPM6 magnesium transporter in kidney were associated with severity of calcification. Calcification prone fetuin-A deficient mice were alternatively treated with dietary phosphate restriction, magnesium supplementation, or by parenteral administration of fetuin-A or pyrophosphate. All treatments markedly reduced soft tissue calcification, demonstrated by computed tomography, histology and tissue calcium measurement.\n\nConclusionsWe show that pathological ectopic calcification in fetuin-A deficient DBA/2 mice is caused by a compound deficiency of three major extracellular and systemic inhibitors of calcification, namely fetuin-A, pyrophosphate, and magnesium. All three of these are individually known to contribute to stabilize protein-mineral complexes and thus inhibit mineral precipitation from extracellular fluid. We show for the first time a compound triple deficiency that can be treated by simple dietary or parenteral supplementation. This is of special importance in patients with advanced CKD, who commonly exhibit reduced serum fetuin-A, pyrophosphate and magnesium levels.\n\nSubject CodesAnimal Models of Human Disease, Fibrosis, Inflammation, Proteomics, Peripheral Vascular Disease

physiology↗