Chen, CP;Zhang, J;Zhang, B;Hassan, MG;Hane, K;
| DOI: 10.1002/jbm4.10638
The adaptive response of the mandible and temporomandibular joint (TMJ) to altered occlusion in juvenile patients is presently unclear. To address this question, we established a mouse model in which all molars were extracted from the maxillary right quadrant in pre-pubertal, 3-week-old mice and analyzed morphological, tissue, cellular, and molecular changes in the mandible and condyle three weeks later. Unilateral loss of maxillary molars led to significant, robust, bilateral changes, primarily in condylar morphology, including antero-posterior narrowing of the condylar head and neck and increased convexity at the condylar surface, as determined by geometric morphometric analysis. Furthermore, both condyles in experimental mice exhibited a degenerative phenotype, which included decreased bone volume and increased mineral density near the condylar head surface compared to control mice. Changes in condylar morphology and mineralized tissue composition were associated with alterations in the cellular architecture of the mandibular condylar cartilage, including increased expression of markers for mature (Col2a1) and hypertrophic (Col10a1) chondrocytes, suggesting a shift towards differentiating chondrocytes. Our results show significant bilateral condylar morphological changes, alterations in tissue composition, cellular organization, and molecular expression, as well as degenerative disease, in response to the unilateral loss of teeth. Our study provides a relatively simple, tractable mouse tooth extraction system that will be of utility in uncovering the cellular and molecular mechanisms of condylar and mandibular adaptation in response to altered occlusion.
Widmer, FC;O'Toole, SM;Keller, GB;
PMID: 35170429 | DOI: 10.7554/eLife.71476
The experience of coupling between motor output and visual feedback is necessary for the development of visuomotor skills and shapes visuomotor integration in visual cortex. Whether these experience-dependent changes of responses in V1 depend on modifications of the local circuit or are the consequence of circuit changes outside of V1 remains unclear. Here, we probed the role of N-methyl-d-aspartate (NMDA) receptor-dependent signaling, which is known to be involved in neuronal plasticity, in mouse primary visual cortex (V1) during visuomotor development. We used a local knockout of NMDA receptors and a photoactivatable inhibition of CaMKII in V1 during the first visual experience to probe for changes in neuronal activity in V1 as well as the influence on performance in a visuomotor task. We found that a knockout of NMDA receptors before, but not after, first visuomotor experience reduced responses to unpredictable stimuli, diminished the suppression of predictable feedback in V1, and impaired visuomotor skill learning later in life. Our results demonstrate that NMDA receptor-dependent signaling in V1 is critical during the first visuomotor experience for shaping visuomotor integration and enabling visuomotor skill learning.
Clinical science (London, England : 1979)
Kumar, R;Lee, MH;Kassa, B;Fonseca Balladares, DC;Mickael, C;Sanders, L;Andruska, A;Kumar, M;Spiekerkoetter, E;Bandeira, A;Stenmark, KR;Tuder, RM;Graham, BB;
PMID: 37014925 | DOI: 10.1042/CS20220642
Pulmonary hypertension (PH) can occur as a complication of schistosomiasis. In humans, schistosomiasis-PH persists despite antihelminthic therapy and parasite eradication. We hypothesized that persistent disease arises as a consequence of exposure repetition.Following intraperitoneal sensitization, mice were experimentally exposed to Schistosoma eggs by intravenous injection, either once or three times repeatedly. The phenotype was characterized by right heart catheterization and tissue analysis.Following intraperitoneal sensitization, a single intravenous Schistosoma egg exposure resulted in a PH phenotype that peaked at 7-14 days, followed by spontaneous resolution. Three sequential exposures resulted in a persistent PH phenotype. Inflammatory cytokines were not significantly different between mice exposed to one or three egg doses, but there was an increase in perivascular fibrosis in those who received three egg doses. Significant perivascular fibrosis was also observed in autopsy specimens from patients who died of this condition.Repeatedly exposing mice to schistosomiasis causes a persistent PH phenotype, accompanied by perivascular fibrosis. Perivascular fibrosis may contribute to the persistent schistosomiasis-PH observed in humans with this disease.
Sieber, P;Schäfer, A;Lieberherr, R;Caimi, SL;Lüthi, U;Ryge, J;Bergmann, JH;Le Goff, F;Stritt, M;Blattmann, P;Renault, B;Rammelt, P;Sempere, B;Freti, D;Studer, R;White, ES;Birker-Robaczewska, M;Boucher, M;Nayler, O;
PMID: 36520540 | DOI: 10.1172/jci.insight.154719
In the progression phase of idiopathic pulmonary fibrosis (IPF) the normal alveolar structure of the lung is lost and replaced by remodeled fibrotic tissue and by bronchiolized cystic airspaces. Although these are characteristic features of IPF, knowledge of specific interactions between these pathological processes is limited. Here, the interaction of lung epithelial and lung mesenchymal cells was investigated in a co-culture model of human primary airway epithelial cells (EC) and lung fibroblasts (FB). Single-cell RNA sequencing (sc-RNA-seq) revealed that the starting EC population was heterogenous and enriched for cells with a basal cell signature. Furthermore, fractions of the initial EC and FB cell populations adopted distinct pro-fibrotic cell differentiation states upon co-cultivation, resembling specific cell populations that were previously identified in lungs of IPF patients. Transcriptomic analysis revealed active nuclear factor NF-kappa-B (NF-κB) signaling early in the co-cultured EC and FB cells and the identified NF-κB expression signatures were also found in "HAS1 High FB" and "PLIN2+ FB" populations from IPF patient lungs. Pharmacological blockade of NF-κB signaling attenuated specific phenotypic changes of EC and prevented FB-mediated interleukin-6 (IL6), interleukin-8 (IL-8) and C-X-C motif chemokine ligand 6 (CXCL6) cytokine secretion, as well as collagen alpha-1(I) chain (COL1A1) and alpha-smooth muscle actin (α-SMA) accumulation. Thus, we identified NF-κB as a potential mediator, linking epithelial pathobiology with fibrogenesis.