Ion channel mRNA distribution and expression in the sinoatrial node and right atrium of dogs and monkeys
Journal of Toxicologic Pathology
SANO, T;YASUNO, H;WATANABE, T;
| DOI: 10.1293/tox.2020-0089
There are limited data on the gene expression profiles of ion channels in the sinoatrial node (SAN) of dogs and monkeys. In this study, the messenger RNA (mRNA) expression profiles of various ion channels in the SAN of naïve dogs and monkeys were examined using RNAscope _in situ _hybridization and compared with those in the surrounding right atrium (RA) of each species. Regional-specific Cav1.3 and HCN4 expression was observed in the SAN of dogs and monkeys. Additionally, HCN1 in dogs was only expressed in the SAN group. The expression profiles of Cav3.1 and Cav3.2 in the SAN and RA were completely different between dogs and monkeys. Dog hearts only expressed Cav3.2; however, Cav3.1 was detected only in monkeys, and the expression score in the SAN was slightly higher than that in the RA. Although Kir3.1 and NCX1 in dogs were equally expressed in both the SAN and RA, the expression scores of these genes in the SAN of monkeys were slightly higher than those in the RA. The Kir3.4 expression score in the SAN of dogs and monkeys was also slightly higher than that in the RA. The mRNA expression scores of Kv11.1/ERG and KvLQT1 were equally observed in both the SAN and RA of dogs and monkeys. HCN2 was not detected in dogs and monkeys. In summary, we used RNAscope to demonstrate the SAN-specific gene expression patterns of ion channels, which may be useful in explaining the effect of pacemaking and/or hemodynamic effects in nonclinical studies.
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.
Scheiber, AL;Wilkinson, KJ;Suzuki, A;Enomoto-Iwamoto, M;Kaito, T;Cheah, KS;Iwamoto, M;Leikin, S;Otsuru, S;
PMID: 34990412 | DOI: 10.1172/jci.insight.149636
Short stature is a major skeletal phenotype in osteogenesis imperfecta (OI), a genetic disorder mainly caused by mutations in genes encoding type I collagen. However, the underlying mechanism is poorly understood and no effective treatment is available. In OI mice that carry a G610C mutation in COL1A2, we previously found that mature hypertrophic chondrocytes (HCs) are exposed to cell stress due to accumulation of misfolded mutant type I procollagen in the endoplasmic reticulum (ER). By fate mapping analysis of HCs in G610C OI mice, we found that HCs stagnate in the growth plate, inhibiting translocation of HC descendants to the trabecular area and their differentiation to osteoblasts. Treatment with 4-phenylbutyric acid (4PBA), a chemical chaperone, restored HC ER structure and rescued this inhibition, resulting in enhanced longitudinal bone growth in G610C OI mice. Interestingly, the effects of 4PBA on ER dilation were limited in osteoblasts and the bone fragility was not ameliorated. These results highlight the importance of targeting HCs to treat growth deficiency in OI. Our findings demonstrate that HC dysfunction induced by ER disruption plays a critical role in the pathogenesis of OI growth deficiency, which lays the foundation for developing new therapies for OI.
Journal of developmental biology
Vonk, AC;Hasel-Kolossa, SC;Lopez, GA;Hudnall, ML;Gamble, DJ;Lozito, TP;
PMID: 35225965 | DOI: 10.3390/jdb10010012
(1) Background: Lizard tail regeneration provides a unique model of blastema-based tissue regeneration for large-scale appendage replacement in amniotes. Green anole lizard (Anolis carolinensis) blastemas contain fibroblastic connective tissue cells (FCTCs), which respond to hedgehog signaling to create cartilage in vivo. However, an in vitro model of the blastema has not previously been achieved in culture. (2) Methods: By testing two adapted tissue dissociation protocols and two optimized media formulations, lizard tail FCTCs were pelleted in vitro and grown in a micromass blastema organoid culture. Pellets were analyzed by histology and in situ hybridization for FCTC and cartilage markers alongside staged original and regenerating lizard tails. (3) Results: Using an optimized serum-free media and a trypsin- and collagenase II-based dissociation protocol, micromass blastema organoids were formed. Organoid cultures expressed FCTC marker CDH11 and produced cartilage in response to hedgehog signaling in vitro, mimicking in vivo blastema and tail regeneration. (4) Conclusions: Lizard tail blastema regeneration can be modeled in vitro using micromass organoid culture, recapitulating in vivo FCTC marker expression patterns and chondrogenic potential.
American journal of physiology. Lung cellular and molecular physiology
Danopoulos, S;Belgacemi, R;Hein, RFC;Miller, AJ;Deutsch, GH;Glass, I;Spence, JR;Al Alam, D;
PMID: 36791060 | DOI: 10.1152/ajplung.00316.2022
Fibroblast growth factor (FGF) signaling is known to play an important role in lung organogenesis. However, we recently demonstrated that FGF10 fails to induce branching in human fetal lungs as is observed in mouse. Our previous human fetal lung RNA sequencing data exhibited increased FGF18 during the pseudoglandular stage of development, suggestive of its importance in human lung branching morphogenesis. Whereas it has been previously reported that FGF18 is critical during alveologenesis, few studies have described its implication in lung branching, specifically in human. Therefore, we aimed to determine the role of FGF18 in human lung branching morphogenesis. Human fetal lung explants within the pseudoglandular stage of development were treated with recombinant human FGF18 in air-liquid interface culture. Explants were analyzed grossly to assess differences in branching pattern, as well as at the cellular and molecular levels. FGF18 treatment promoted branching in explant cultures and demonstrated increased epithelial proliferation as well as maintenance of the double positive SOX2/SOX9 distal bud progenitor cells, confirming its role in human lung branching morphogenesis. In addition, FGF18 treated explants displayed increased expression of SOX9, FN1, and COL2A1 within the mesenchyme, all factors that are important to chondrocyte differentiation. In humans, cartilaginous airways extend deep into the lung up to the 12th generation of branching whereas in mouse these are restricted to the trachea and main bronchi. Therefore, our data suggest that FGF18 promotes human lung branching morphogenesis through regulating mesenchymal progenitor cells.
Joo A, Long R, Cheng Z, Alexander C, Chang W, Klein OD.
PMID: 27130872 | DOI: 10.1016/j.bone.2016.04.023
Skeletal development is regulated by the coordinated activity of signaling molecules that are both produced locally by cartilage and bone cells and also circulate systemically. During embryonic development and postnatal bone remodeling, receptor tyrosine kinase (RTK) superfamily members play critical roles in the proliferation, survival, and differentiation of chondrocytes, osteoblasts, osteoclasts, and other bone cells. Recently, several molecules that regulate RTK signaling have been identified, including the four members of the Sprouty (Spry) family (Spry1-4). We report that Spry2 plays an important role in regulation of endochondral bone formation. Mice in which the Spry2 gene has been deleted have defective chondrogenesis and endochondral bone formation, with a postnatal decrease in skeletal size and trabecular bone mass. In these constitutive Spry2 mutants, both chondrocytes and osteoblasts undergo increased cell proliferation and impaired terminal differentiation. Tissue-specific Spry2 deletion by either osteoblast- (Col1-Cre) or chondrocyte- (Col2-Cre) specific drivers led to decreased relative bone mass, demonstrating the critical role of Spry2 in both cell types. Molecular analyses of signaling pathways in Spry2-/- mice revealed an unexpected upregulation of BMP signaling and decrease in RTK signaling. These results identify Spry2 as a critical regulator of endochondral bone formation that modulates signaling in both osteoblast and chondrocyte lineages.
Miura Y, Ota S, Peterlin M, McDevitt G, Kanazawa S.
| DOI: 10.1002/jbm4.10132
Specific MHC class II genes result in a high susceptibility to rheumatoid arthritis (RA), with co‐stimulatory molecules working together with MHC class II during the progression of the disease. To elucidate the involvement of the B7.1 co‐stimulatory molecule in RA, we analyzed the phenotype of B7.1 transgenic (named D1BC) mice and the sequential differentiation of synovial fibroblasts (SFs) by studying the expression of chondrogenic and osteogenic lineage markers together with lineage tracing experiment using B7.1 transgene in vivo. The B7.1 transgene was driven by a collagen type II (CII) promoter and enhancer in the D1BC mouse. A low‐dose of bovine CII (bCII) was used to induce chronic articular inflammation with interstitial pneumonitis. Joint damage was analyzed by histopathological examination and computed tomography. B7.1 was expressed in articular cartilage and SFs of D1BC mice. Chronic inflammatory arthritis in bCII‐D1BC mouse shared common features with those found in patients with RA, such as pannus formation, bone destruction, osteoporosis, and joint ankylosis. A subpopulation of SFs (Runx2+, Sox9+, Col10a1+, Osx+ and CX‐) in the pannus was classified as osteochondrogenic lineage rather than mesenchymal stromal lineage. These cells underwent differentiation into osteogenic lineage via hypertrophic chondrocytes at the end of the chronic phase. The ectopic expression of B7.1 in chondrocytes and SFs leads to an increased susceptibility to chronic inflammatory arthritis and subsequent new bone formation, reminiscent of ankylosis. The regulation of cartilage remodeling in pannus tissue is an important consideration in the treatment of RA.
Mizuhashi K, Nagata M, Matsushita Y, Ono W and Ono N
PMID: 30888720 | DOI: 10.1002/jbmr.3719
The growth plate provides a substantial source of mesenchymal cells in the endosteal marrow space during endochondral ossification. The current model postulates that a group of chondrocytes in the hypertrophic zone can escape from apoptosis and transform into cells that eventually become osteoblasts in an area beneath the growth plate. The growth plate is composed of cells with various morphologies; particularly, at the periphery of the growth plate immediately adjacent to the perichondrium are 'borderline' chondrocytes, which align perpendicularly to other chondrocytes. However, in vivo cell fates of these special chondrocytes have not been revealed. Here we show that borderline chondrocytes in growth plates behave as transient mesenchymal precursor cells for osteoblasts and marrow stromal cells. A single cell RNA-seq analysis revealed subpopulations of Col2a1-creER-marked neonatal chondrocytes and their cell-type specific markers. A tamoxifen pulse to Pthrp-creER mice in the neonatal stage (before the resting zone was formed) preferentially marked borderline chondrocytes. Following the chase, these cells marched into the nascent marrow space, expanded in the metaphyseal marrow and became Col(2.3kb)-GFP(+) osteoblasts and Cxcl12-GFP(high) reticular stromal 'CAR' cells. Interestingly, these borderline chondrocyte-derived marrow cells were short-lived, as they were significantly reduced during adulthood. These findings demonstrate based on in vivo lineage-tracing experiments that borderline chondrocytes in the peripheral growth plate are a particularly important route for producing osteoblasts and marrow stromal cells in growing murine endochondral bones. A special microenvironment neighboring the osteogenic perichondrium might endow these chondrocytes with an enhanced potential to differentiate into marrow mesenchymal cells. This article is protected by copyright. All rights reserved.
Tommiska J, Känsäkoski J, Skibsbye L, Vaaralahti K, Liu X, Lodge EJ, Tang C, Yuan L, Fagerholm R, Kanters JK, Lahermo P, Kaunisto M, Keski-Filppula R, Vuoristo S, Pulli K, Ebeling T, Valanne L, Sankila EM, Kivirikko S, Lääperi M, Casoni F, Giacobini P, Ph
PMID: 29097701 | DOI: 10.1038/s41467-017-01429-z
Familial growth hormone deficiency provides an opportunity to identify new genetic causes of short stature. Here we combine linkage analysis with whole-genome resequencing in patients with growth hormone deficiency and maternally inherited gingival fibromatosis. We report that patients from three unrelated families harbor either of two missense mutations, c.347G>T p.(Arg116Leu) or c.1106C>T p.(Pro369Leu), in KCNQ1, a gene previously implicated in the long QT interval syndrome. Kcnq1 is expressed in hypothalamic GHRH neurons and pituitary somatotropes. Co-expressing KCNQ1 with the KCNE2 β-subunit shows that both KCNQ1 mutants increase current levels in patch clamp analyses and are associated with reduced pituitary hormone secretion from AtT-20 cells. In conclusion, our results reveal a role for the KCNQ1 potassium channel in the regulation of human growth, and show that growth hormone deficiency associated with maternally inherited gingival fibromatosis is an allelic disorder with cardiac arrhythmia syndromes caused by KCNQ1 mutations.
Mizuhashi K, Ono W, Matsushita Y, Sakagami N, Takahashi A, Saunders TL, Nagasawa T, Kronenberg HM, Ono N.
PMID: - | DOI: 10.1038/s41586-018-0662-5
Skeletal stem cells regulate bone growth and homeostasis by generating diverse cell types, including chondrocytes, osteoblasts and marrow stromal cells. The emerging concept postulates that there exists a distinct type of skeletal stem cell that is closely associated with the growth plate1–4, which is a type of cartilaginous tissue that has critical roles in bone elongation5. The resting zone maintains the growth plate by expressing parathyroid hormone-related protein (PTHrP), which interacts with Indian hedgehog (Ihh) that is released from the hypertrophic zone6–10, and provides a source of other chondrocytes11. However, the identity of skeletal stem cells and how they are maintained in the growth plate are unknown. Here we show, in a mouse model, that skeletal stem cells are formed among PTHrP-positive chondrocytes within the resting zone of the postnatal growth plate. PTHrP-positive chondrocytes expressed a panel of markers for skeletal stem and progenitor cells, and uniquely possessed the properties of skeletal stem cells in cultured conditions. Cell-lineage analysis revealed that PTHrP-positive chondrocytes in the resting zone continued to form columnar chondrocytes in the long term; these chondrocytes underwent hypertrophy, and became osteoblasts and marrow stromal cells beneath the growth plate. Transit-amplifying chondrocytes in the proliferating zone—which was concertedly maintained by a forward signal from undifferentiated cells (PTHrP) and a reverse signal from hypertrophic cells (Ihh)—provided instructive cues to maintain the cell fates of PTHrP-positive chondrocytes in the resting zone. Our findings unravel a type of somatic stem cell that is initially unipotent and acquires multipotency at the post-mitotic stage, underscoring the malleable nature of the skeletal cell lineage. This system provides a model in which functionally dedicated stem cells and their niches are specified postnatally, and maintained throughout tissue growth by a tight feedback regulation system.
Taieb, M;Ghannoum, D;Barré, L;Ouzzine, M;
PMID: 37296099 | DOI: 10.1038/s41419-023-05875-0
Genetic mutations in the Xylt1 gene are associated with Desbuquois dysplasia type II syndrome characterized by sever prenatal and postnatal short stature. However, the specific role of XylT-I in the growth plate is not completely understood. Here, we show that XylT-I is expressed and critical for the synthesis of proteoglycans in resting and proliferative but not in hypertrophic chondrocytes in the growth plate. We found that loss of XylT-I induces hypertrophic phenotype-like of chondrocytes associated with reduced interterritorial matrix. Mechanistically, deletion of XylT-I impairs the synthesis of long glycosaminoglycan chains leading to the formation of proteoglycans with shorter glycosaminoglycan chains. Histological and Second Harmonic Generation microscopy analysis revealed that deletion of XylT-I accelerated chondrocyte maturation and prevents chondrocytes columnar organization and arrangement in parallel of collagen fibers in the growth plate, suggesting that XylT-I controls chondrocyte maturation and matrix organization. Intriguingly, loss of XylT-I induced at embryonic stage E18.5 the migration of progenitor cells from the perichondrium next to the groove of Ranvier into the central part of epiphysis of E18.5 embryos. These cells characterized by higher expression of glycosaminoglycans exhibit circular organization then undergo hypertrophy and death creating a circular structure at the secondary ossification center location. Our study revealed an uncovered role of XylT-I in the synthesis of proteoglycans and provides evidence that the structure of glycosaminoglycan chains of proteoglycans controls chondrocyte maturation and matrix organization.
Matsushita, Y;Chu, AKY;Tsutsumi-Arai, C;Orikasa, S;Nagata, M;Wong, SY;Welch, JD;Ono, W;Ono, N;
PMID: 36443296 | DOI: 10.1038/s41467-022-34804-6
In endochondral bone development, bone-forming osteoblasts and bone marrow stromal cells have dual origins in the fetal cartilage and its surrounding perichondrium. However, how early perichondrial cells distinctively contribute to developing bones remain unidentified. Here we show using in vivo cell-lineage analyses that Dlx5+ fetal perichondrial cells marked by Dlx5-creER do not generate cartilage but sustainably contribute to cortical bone and marrow stromal compartments in a manner complementary to fetal chondrocyte derivatives under the regulation of Hedgehog signaling. Postnatally, Dlx5+ fetal perichondrial cell derivatives preferentially populate the diaphyseal marrow stroma with a dormant adipocyte-biased state and are refractory to parathyroid hormone-induced bone anabolism. Therefore, early perichondrial cells of the fetal cartilage are destined to become an adipogenic subset of stromal cells in postnatal diaphyseal bone marrow, supporting the theory that the adult bone marrow stromal compartments are developmentally prescribed within the two distinct cells-of-origins of the fetal bone anlage.
