gp130/STAT3 signaling is required for homeostatic proliferation and anabolism in postnatal growth plate and articular chondrocytes

Growth of long bones and vertebrae is maintained postnatally by a long-lasting pool of progenitor cells. Little is known about the molecular mechanisms that regulate the output and maintenance of the cells that give rise to mature cartilage. Here we demonstrate that postnatal chondrocyte-specific deletion of a transcription factor Stat3 results in severely reduced proliferation coupled with increased hypertrophy, growth plate fusion, stunting and signs of progressive dysfunction of the articular cartilage. This effect is dimorphic, with females more strongly affected than males. Chondrocyte-specific deletion of the IL-6 family cytokine receptor gp130, which activates Stat3, phenocopied Stat3-deletion; deletion of Lifr, one of many co-receptors that signals through gp130, resulted in a milder phenotype. These data define a new molecular circuit that regulates chondrogenic cell maintenance and output and reveals a novel, hitherto unrecognized function of IL-6 cytokines in the skeletal system with direct implications for skeletal development and regeneration.

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Liver X Receptor activation regulates genes involved in lipid homeostasis in developing chondrocytes

10.1101/705269 ◽

2019 ◽

Author(s):

Margaret Man-Ger Sun ◽

Frank Beier

Keyword(s):

Lipid Metabolism ◽

Growth Plate ◽

Cholesterol Efflux ◽

Molecular Mechanisms ◽

Bone Growth ◽

Articular Chondrocytes ◽

Protein Localization ◽

Receptor Activation ◽

Lipid Homeostasis ◽

Growth Plate Chondrocytes

AbstractObjectiveOsteoarthritis (OA) is the most common type of arthritis and causes debilitating symptoms and decreased quality of life. Currently available treatment options target symptoms but do not address the underlying issue of joint tissue degeneration. As such, a better understanding of the molecular mechanisms maintaining cartilage health is needed for developing novel therapeutic strategies. Liver X Receptors (LXRs) are nuclear receptors that have been previously shown to offer protection against OA. This is potentially due to suppression of chondrocyte hypertrophy in endochondral bone growth in response to LXR activation. In order to better understand the regulatory mechanisms behind this effect, we aimed to systematically examine LXR’s effects on growth plate chondrocyte gene expression.MethodsPrimary chondrocytes isolated from the long bones of E15.5 mice were treated with the specific LXR agonist, GW3965, and RNA was isolated for Affymetrix microarrays followed by real time qPCR validation. Bioinformatics analyses were performed using Gene Ontology (GO) and KEGG pathway analysis. Immunohistochemistry was conducted to examine protein localization of LXR and identified targets in GW3965-treated E15.5 tibiae compared to control.ResultsActivation of LXR in primary growth plate chondrocytes resulted in differential regulations of various genes involved in lipid metabolism, including several genes involved in cholesterol efflux. This pattern was compared to LXR activation in immature murine articular chondrocytes (IMACs), which revealed similar roles in lipid homeostasis. Immunohistochemical analysis of LXR and its identified targets Abca1 and Srebf1 revealed preferential protein localization to pre-hypertrophic and resting chondrocytes in GW3965-treated tibial growth plates compared to controls.ConclusionOur findings show for the first time that LXR activation alters expression of lipid metabolism genes in growth plate chondrocytes, in part through activation of molecules responsible for cellular cholesterol efflux. This provides insight into potential mechanisms through which LXR regulates cellular metabolism to alter chondrocyte behavior and phenotype.

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SOX9 keeps growth plates and articular cartilage healthy by inhibiting chondrocyte dedifferentiation/osteoblastic redifferentiation

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2019152118 ◽

2021 ◽

Vol 118 (8) ◽

pp. e2019152118

Author(s):

Abdul Haseeb ◽

Ranjan Kc ◽

Marco Angelozzi ◽

Charles de Charleroy ◽

Danielle Rux ◽

...

Keyword(s):

Articular Cartilage ◽

Growth Plate ◽

Molecular Mechanisms ◽

High Throughput Sequencing ◽

Articular Chondrocytes ◽

Treatment Options ◽

Cell Lineage ◽

Bmp Signaling ◽

Conditional Knockout ◽

Growth Plate Chondrocytes

Cartilage is essential throughout vertebrate life. It starts developing in embryos when osteochondroprogenitor cells commit to chondrogenesis, activate a pancartilaginous program to form cartilaginous skeletal primordia, and also embrace a growth-plate program to drive skeletal growth or an articular program to build permanent joint cartilage. Various forms of cartilage malformation and degeneration diseases afflict humans, but underlying mechanisms are still incompletely understood and treatment options suboptimal. The transcription factor SOX9 is required for embryonic chondrogenesis, but its postnatal roles remain unclear, despite evidence that it is down-regulated in osteoarthritis and heterozygously inactivated in campomelic dysplasia, a severe skeletal dysplasia characterized postnatally by small stature and kyphoscoliosis. Using conditional knockout mice and high-throughput sequencing assays, we show here that SOX9 is required postnatally to prevent growth-plate closure and preosteoarthritic deterioration of articular cartilage. Its deficiency prompts growth-plate chondrocytes at all stages to swiftly reach a terminal/dedifferentiated stage marked by expression of chondrocyte-specific (Mgp) and progenitor-specific (Nt5e and Sox4) genes. Up-regulation of osteogenic genes (Runx2, Sp7, and Postn) and overt osteoblastogenesis quickly ensue. SOX9 deficiency does not perturb the articular program, except in load-bearing regions, where it also provokes chondrocyte-to-osteoblast conversion via a progenitor stage. Pathway analyses support roles for SOX9 in controlling TGFβ and BMP signaling activities during this cell lineage transition. Altogether, these findings deepen our current understanding of the cellular and molecular mechanisms that specifically ensure lifelong growth-plate and articular cartilage vigor by identifying osteogenic plasticity of growth-plate and articular chondrocytes and a SOX9-countered chondrocyte dedifferentiation/osteoblast redifferentiation process.

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RECENT RESEARCH ON THE GROWTH PLATE: Advances in fibroblast growth factor signaling in growth plate development and disorders

Journal of Molecular Endocrinology ◽

10.1530/jme-14-0012 ◽

2014 ◽

Vol 53 (1) ◽

pp. T11-T34 ◽

Cited By ~ 17

Author(s):

Yangli Xie ◽

Siru Zhou ◽

Hangang Chen ◽

Xiaolan Du ◽

Lin Chen

Keyword(s):

Growth Factor ◽

Fibroblast Growth Factor ◽

Growth Plate ◽

Endochondral Ossification ◽

Molecular Mechanisms ◽

Skeletal Development ◽

Vital Role ◽

Growth Factor Signaling ◽

Missense Mutations ◽

Fibroblast Growth

Skeletons are formed through two distinct developmental actions, intramembranous ossification and endochondral ossification. During embryonic development, most bone is formed by endochondral ossification. The growth plate is the developmental center for endochondral ossification. Multiple signaling pathways participate in the regulation of endochondral ossification. Fibroblast growth factor (FGF)/FGF receptor (FGFR) signaling has been found to play a vital role in the development and maintenance of growth plates. Missense mutations inFGFsandFGFRscan cause multiple genetic skeletal diseases with disordered endochondral ossification. Clarifying the molecular mechanisms of FGFs/FGFRs signaling in skeletal development and genetic skeletal diseases will have implications for the development of therapies for FGF-signaling-related skeletal dysplasias and growth plate injuries. In this review, we summarize the recent advances in elucidating the role of FGFs/FGFRs signaling in growth plate development, genetic skeletal disorders, and the promising therapies for those genetic skeletal diseases resulting from FGFs/FGFRs dysfunction. Finally, we also examine the potential important research in this field in the future.

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Growth Plate Chondrocytes: Skeletal Development, Growth and Beyond

International Journal of Molecular Sciences ◽

10.3390/ijms20236009 ◽

2019 ◽

Vol 20 (23) ◽

pp. 6009 ◽

Cited By ~ 10

Author(s):

Shawn A. Hallett ◽

Wanida Ono ◽

Noriaki Ono

Keyword(s):

Growth Plate ◽

Bone Marrow Stromal Cells ◽

Skeletal Development ◽

Cell Types ◽

Postnatal Growth ◽

Lineage Tracing ◽

Molecular Characteristics ◽

Growth Plate Chondrocytes ◽

Parathyroid Hormone Related Protein

Growth plate chondrocytes play central roles in the proper development and growth of endochondral bones. Particularly, a population of chondrocytes in the resting zone expressing parathyroid hormone-related protein (PTHrP) is now recognized as skeletal stem cells, defined by their ability to undergo self-renewal and clonally give rise to columnar chondrocytes in the postnatal growth plate. These chondrocytes also possess the ability to differentiate into a multitude of cell types including osteoblasts and bone marrow stromal cells during skeletal development. Using single-cell transcriptomic approaches and in vivo lineage tracing technology, it is now possible to further elucidate their molecular properties and cellular fate changes. By discovering the fundamental molecular characteristics of these cells, it may be possible to harness their functional characteristics for skeletal growth and regeneration. Here, we discuss our current understanding of the molecular signatures defining growth plate chondrocytes.

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Home for a rest: stem cell niche of the postnatal growth plate

Journal of Endocrinology ◽

10.1530/joe-20-0045 ◽

2020 ◽

Vol 246 (1) ◽

pp. R1-R11 ◽

Cited By ~ 2

Author(s):

Julian C Lui

Keyword(s):

Stem Cell ◽

Growth Plate ◽

Stem Cell Niche ◽

Molecular Mechanisms ◽

Bone Growth ◽

Postnatal Growth ◽

Lineage Tracing ◽

Endocrine Regulation ◽

Technological Advances ◽

Cell Niche

The resting zone houses a group of slowly proliferating ‘reserve’ chondrocytes and has long been speculated to serve as the stem cell niche of the postnatal growth plate. But are these resting chondrocytes bona fide stem cells? Recent technological advances in lineage tracing and next-generation sequencing have finally allowed researchers to answer this question. Several recent studies have also shed light into the signaling pathways and molecular mechanisms involved in the maintenance of resting chondrocytes, thus providing us with important new insights into the role of the resting zone in the paracrine and endocrine regulation of childhood bone growth.

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Ultrastructural and molecular analysis of the origin and differentiation of cells mediating brittle star skeletal regeneration

BMC Biology ◽

10.1186/s12915-020-00937-7 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Laura Piovani ◽

Anna Czarkwiani ◽

Cinzia Ferrario ◽

Michela Sugni ◽

Paola Oliveri

Keyword(s):

Molecular Mechanisms ◽

Close Contact ◽

Skeletal Development ◽

Morphological Differentiation ◽

Brittle Star ◽

Marker Genes ◽

Body Parts ◽

Coelomic Cavity ◽

Expression Of Genes ◽

Skeletal Regeneration

Abstract Background Regeneration is the ability to re-grow body parts or tissues after trauma, and it is widespread across metazoans. Cells involved in regeneration can arise from a pool of undifferentiated proliferative cells or be recruited from pre-existing differentiated tissues. Both mechanisms have been described in different phyla; however, the cellular and molecular mechanisms employed by different animals to restore lost tissues as well as the source of cells involved in regeneration remain largely unknown. Echinoderms are a clade of deuterostome invertebrates that show striking larval and adult regenerative abilities in all extant classes. Here, we use the brittle star Amphiura filiformis to investigate the origin and differentiation of cells involved in skeletal regeneration using a combination of microscopy techniques and molecular markers. Results Our ultrastructural analyses at different regenerative stages identify a population of morphologically undifferentiated cells which appear in close contact with the proliferating epithelium of the regenerating aboral coelomic cavity. These cells express skeletogenic marker genes, such as the transcription factor alx1 and the differentiation genes c-lectin and msp130L, and display a gradient of morphological differentiation from the aboral coelomic cavity towards the epidermis. Cells closer to the epidermis, which are in contact with developing spicules, have the morphology of mature skeletal cells (sclerocytes), and express several skeletogenic transcription factors and differentiation genes. Moreover, as regeneration progresses, sclerocytes show a different combinatorial expression of genes in various skeletal elements. Conclusions We hypothesize that sclerocyte precursors originate from the epithelium of the proliferating aboral coelomic cavity. As these cells migrate towards the epidermis, they differentiate and start secreting spicules. Moreover, our study shows that molecular and cellular processes involved in skeletal regeneration resemble those used during skeletal development, hinting at a possible conservation of developmental programmes during adult regeneration. Finally, we highlight that many genes involved in echinoderm skeletogenesis also play a role in vertebrate skeleton formation, suggesting a possible common origin of the deuterostome endoskeleton pathway.

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The laterodorsal tegmentum-ventral tegmental area circuit controls depression-like behaviors by activating ErbB4 in DA neurons

Molecular Psychiatry ◽

10.1038/s41380-021-01137-7 ◽

2021 ◽

Author(s):

Hongsheng Wang ◽

Wanpeng Cui ◽

Wenbing Chen ◽

Fang Liu ◽

Zhaoqi Dong ◽

...

Keyword(s):

Ventral Tegmental Area ◽

Molecular Mechanisms ◽

Critical Role ◽

Coping With Stress ◽

Chemical Genetic ◽

Chronic Social Defeat Stress ◽

Ventral Tegmental ◽

Laterodorsal Tegmentum ◽

Specific Deletion

AbstractDopamine (DA) neurons in the ventral tegmental area (VTA) are critical to coping with stress. However, molecular mechanisms regulating their activity and stress-induced depression were not well understood. We found that the receptor tyrosine kinase ErbB4 in VTA was activated in stress-susceptible mice. Deleting ErbB4 in VTA or in DA neurons, or chemical genetic inhibition of ErbB4 kinase activity in VTA suppressed the development of chronic social defeat stress (CSDS)-induced depression-like behaviors. ErbB4 activation required the expression of NRG1 in the laterodorsal tegmentum (LDTg); LDTg-specific deletion of NRG1 inhibited depression-like behaviors. NRG1 and ErbB4 suppressed potassium currents of VTA DA neurons and increased their firing activity. Finally, we showed that acute inhibition of ErbB4 after stress attenuated DA neuron hyperactivity and expression of depression-like behaviors. Together, these observations demonstrate a critical role of NRG1-ErbB4 signaling in regulating depression-like behaviors and identify an unexpected mechanism by which the LDTg-VTA circuit regulates the activity of DA neurons.

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Maternal Uniparental Disomy of Chromosome 20 (UPD(20)mat) as Differential Diagnosis of Silver Russell Syndrome: Identification of Three New Cases

Genes ◽

10.3390/genes12040588 ◽

2021 ◽

Vol 12 (4) ◽

pp. 588

Author(s):

Pierpaola Tannorella ◽

Daniele Minervino ◽

Sara Guzzetti ◽

Alessandro Vimercati ◽

Luciano Calzari ◽

...

Keyword(s):

Growth Retardation ◽

Molecular Mechanisms ◽

Uniparental Disomy ◽

Postnatal Growth ◽

Molecular Diagnostic ◽

Growth Delay ◽

Molecular Defect ◽

Maternal Uniparental Disomy ◽

Feeding Difficulties ◽

Silver Russell Syndrome

Silver Russell Syndrome (SRS, MIM #180860) is a rare growth retardation disorder in which clinical diagnosis is based on six features: pre- and postnatal growth failure, relative macrocephaly, prominent forehead, body asymmetry, and feeding difficulties (Netchine–Harbison clinical scoring system (NH-CSS)). The molecular mechanisms consist in (epi)genetic deregulations at multiple loci: the loss of methylation (LOM) at the paternal H19/IGF2:IG-DMR (chr11p15.5) (50%) and the maternal uniparental disomy of chromosome 7 (UPD(7)mat) (10%) are the most frequent causes. Thus far, about 40% of SRS remains undiagnosed, pointing to the need to define the rare mechanisms in such a consistent fraction of unsolved patients. Within a cohort of 176 SRS with an NH-CSS ≥ 3, a molecular diagnosis was disclosed in about 45%. Among the remaining patients, we identified in 3 probands (1.7%) with UPD(20)mat (Mulchandani–Bhoj–Conlin syndrome, OMIM #617352), a molecular mechanism deregulating the GNAS locus and described in 21 cases, characterized by severe feeding difficulties associated with failure to thrive, preterm birth, and intrauterine/postnatal growth retardation. Our patients share prominent forehead, feeding difficulties, postnatal growth delay, and advanced maternal age. Their clinical assessment and molecular diagnostic flowchart contribute to better define the characteristics of this rare imprinting disorder and to rank UPD(20)mat as the fourth most common pathogenic molecular defect causative of SRS.

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Impaired skeletal development in interleukin-6–transgenic mice: A model for the impact of chronic inflammation on the growing skeletal system

Arthritis & Rheumatism ◽

10.1002/art.22175 ◽

2006 ◽

Vol 54 (11) ◽

pp. 3551-3563 ◽

Cited By ~ 191

Author(s):

Fabrizio De Benedetti ◽

Nadia Rucci ◽

Andrea Del Fattore ◽

Barbara Peruzzi ◽

Rita Paro ◽

...

Keyword(s):

Transgenic Mice ◽

Chronic Inflammation ◽

Interleukin 6 ◽

Skeletal Development ◽

Skeletal System ◽

The Impact

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Expression of Phosphocitrate-Targeted Genes in Osteoarthritis Menisci

BioMed Research International ◽

10.1155/2014/210469 ◽

2014 ◽

Vol 2014 ◽

pp. 1-17 ◽

Cited By ~ 5

Author(s):

Yubo Sun ◽

David R. Mauerhan ◽

Nury M. Steuerwald ◽

Jane Ingram ◽

Jeffrey S. Kneisl ◽

...

Keyword(s):

Immune System ◽

Molecular Mechanisms ◽

Fibroblast Growth Factor Receptor ◽

Collagen Type ◽

Skeletal Development ◽

Growth Factor Receptor ◽

Type Ii ◽

Immune System Activation ◽

System Activation ◽

Disease Modifying

Phosphocitrate (PC) inhibited calcium crystal-associated osteoarthritis (OA) in Hartley guinea pigs. However, the molecular mechanisms remain elusive. This study sought to determine PC targeted genes and the expression of select PC targeted genes in OA menisci to test hypothesis that PC exerts its disease modifying activity in part by reversing abnormal expressions of genes involved in OA. We found that PC downregulated the expression of numerous genes classified in immune response, inflammatory response, and angiogenesis, including chemokine (C-C motif) ligand 5, Fc fragment of IgG, low affinity IIIb receptor (FCGR3B), and leukocyte immunoglobulin-like receptor, subfamily B member 3 (LILRB3). In contrast, PC upregulated the expression of many genes classified in skeletal development, including collagen type II alpha1, fibroblast growth factor receptor 3 (FGFR3), and SRY- (sex determining region Y-) box 9 (SOX-9). Immunohistochemical examinations revealed higher levels of FCGR3B and LILRB3 and lower level of SOX-9 in OA menisci. These findings indicate that OA is a disease associated with immune system activation and decreased expression of SOX-9 gene in OA menisci. PC exerts its disease modifying activity on OA, at least in part, by targeting immune system activation and the production of extracellular matrix and selecting chondroprotective proteins.

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