scholarly journals Loss of Foxc1 and Foxc2 function in chondroprogenitor cells disrupts endochondral ossification

2021 ◽  
Author(s):  
Asra Almubarak ◽  
Rotem Lavy ◽  
Nikola Srnic ◽  
Yawen Hu ◽  
Devi P. Maripuri ◽  
...  

AbstractEndochondral ossification forms and grows the majority of the mammalian skeleton and is tightly controlled through gene regulatory networks. The forkhead box transcription factors Foxc1 and Foxc2 have been demonstrated to regulate aspects of osteoblast function in the formation of the skeleton but their roles in chondrocytes to control endochondral ossification are less clear. We demonstrate that Foxc1 expression is directly regulated by SOX9 activity, one of the earliest transcription factors to specify the chondrocyte lineages. Moreover we demonstrate that elevelated expression of Foxc1 promotes chondrocyte differentiation in mouse embryonic stem cells and loss of Foxc1 function inhibits chondrogenesis in vitro. Using chondrocyte-targeted deletion of Foxc1 and Foxc2 in mice, we reveal a role for these factors in chondrocyte differentiation in vivo. Loss of both Foxc1 and Foxc2 caused a general skeletal dysplasia predominantly affecting the vertebral column. The long bones of the limb were smaller and mineralization was reduced and organization of the growth plate was disrupted. In particular, the stacked columnar organization of the proliferative chondrocyte layer was reduced in size and cell proliferation in growth plate chondrocytes was reduced. Differential gene expression analysis indicated disrupted expression patterns in chondrogenesis and ossification genes throughout the entire process of endochondral ossification in Col2-cre;Foxc1Δ/Δ;Foxc2Δ/Δ embryos. Our results suggest that Foxc1 and Foxc2 are required for correct chondrocyte differentiation and function. Loss of both genes results in disorganization of the growth plate, reduced chondrocyte proliferation and delays in chondrocyte hypertrophy that prevents correct ossification of the endochondral skeleton.

2002 ◽  
Vol 50 (8) ◽  
pp. 1059-1065 ◽  
Author(s):  
Sherri R. Davies ◽  
Shinji Sakano ◽  
Yong Zhu ◽  
Linda J. Sandell

The control of extracellular matrix (ECM) production is important for the development, maintenance, and repair of cartilage tissues. Matrix molecule synthesis is generally regulated by the rate of gene transcription determined by DNA transcription factors. We have shown that transcription factors Sox9, AP-2, and [delta]EF1 are able to alter the rate of CD-RAP transcription in vitro: Sox9 upregulates, AP-2 exhibits biphasic effects, and [delta]EF1 represses expression of the CD-RAP gene. To correlate these in vitro activities in vivo, transcription factors were co-immunolocalized with ECM proteins in three different cartilage tissues in which the rates of biosynthesis are quite different: articular, meniscal, and growth plate. Immunoreactivities of type II collagen and CD-RAP were higher in growth plate than in either the articular or meniscal cartilages and correlated positively with Sox9 protein. Sox9 staining decreased with hypertrophy and was low in articular and meniscal cartilages. In contrast, AP-2 and [delta]EF1 were low in proliferating chondrocytes but high in lower growth plate, articular, and meniscal cartilages. This increase was also accompanied by intense nuclear staining. These immunohistochemical results are the first to localize both [delta]EF1 and AP-2 to adult articular, meniscal, and growth plate cartilages and provide in vivo correlation of previous molecular biological studies.


Blood ◽  
1998 ◽  
Vol 92 (12) ◽  
pp. 4622-4631 ◽  
Author(s):  
William L. Stanford ◽  
Georgina Caruana ◽  
Katherine A. Vallis ◽  
Maneesha Inamdar ◽  
Michihiro Hidaka ◽  
...  

Abstract We have developed a large-scale, expression-based gene trap strategy to perform genome-wide functional analysis of the murine hematopoietic and vascular systems. Using two different gene trap vectors, we have isolated embryonic stem (ES) cell clones containing lacZreporter gene insertions in genes expressed in blood island and vascular cells, muscle, stromal cells, and unknown cell types. Of 79 clones demonstrating specific expression patterns, 49% and 16% were preferentially expressed in blood islands and/or the vasculature, respectively. The majority of ES clones that expressedlacZ in blood islands also expressed lacZ upon differentiation into hematopoietic cells on OP9 stromal layers. Importantly, the in vivo expression of the lacZ fusion products accurately recapitulated the observed in vitro expression patterns. Expression and sequence analysis of representative clones suggest that this approach will be useful for identifying and mutating novel genes expressed in the developing hematopoietic and vascular systems.


Blood ◽  
1998 ◽  
Vol 92 (12) ◽  
pp. 4622-4631 ◽  
Author(s):  
William L. Stanford ◽  
Georgina Caruana ◽  
Katherine A. Vallis ◽  
Maneesha Inamdar ◽  
Michihiro Hidaka ◽  
...  

We have developed a large-scale, expression-based gene trap strategy to perform genome-wide functional analysis of the murine hematopoietic and vascular systems. Using two different gene trap vectors, we have isolated embryonic stem (ES) cell clones containing lacZreporter gene insertions in genes expressed in blood island and vascular cells, muscle, stromal cells, and unknown cell types. Of 79 clones demonstrating specific expression patterns, 49% and 16% were preferentially expressed in blood islands and/or the vasculature, respectively. The majority of ES clones that expressedlacZ in blood islands also expressed lacZ upon differentiation into hematopoietic cells on OP9 stromal layers. Importantly, the in vivo expression of the lacZ fusion products accurately recapitulated the observed in vitro expression patterns. Expression and sequence analysis of representative clones suggest that this approach will be useful for identifying and mutating novel genes expressed in the developing hematopoietic and vascular systems.


2007 ◽  
Vol 2 ◽  
pp. 117727190700200 ◽  
Author(s):  
Deshira Saiti ◽  
Orly Lacham-Kaplan

In mammalian development, primordial germ cells (PGCs) represent the initial population of cells that are committed to the germ cell lineage. PGCs segregate early in development, triggered by signals from the extra-embryonic ectoderm. They are distinguished from surrounding cells by their unique gene expression patterns. Some of the more common genes used to identify them are Blimp1, Oct3/4, Fragilis, Stella, c-Kit, Mvh, Dazl and Gcna1. These genes are involved in regulating their migration and differentiation, and in maintaining the pluripotency of these cells. Recent research has demonstrated the possibility of obtaining PGCs, and subsequently, mature germ cells from a starting population of embryonic stem cells (ESCs) in culture. This phenomenon has been investigated using a variety of methods, and ESC lines of both mouse and human origin. Embryonic stem cells can differentiate into germ cells of both the male and female phenotype and in one case has resulted in the birth of live pups from the fertilization of oocytes with ESC derived sperm. This finding leads to the prospect of using ESC derived germ cells as a treatment for sterility. This review outlines the evolvement of germ cells from ESCs in vitro in relation to in vivo events.


2008 ◽  
Vol 200 (3) ◽  
pp. 245-258 ◽  
Author(s):  
Kyriaki S Alatzoglou ◽  
Daniel Kelberman ◽  
Mehul T Dattani

Pituitary development is a complex process that depends on the co-ordinated spatial and temporal expression of transcription factors and signalling molecules that culminates in the formation of a complex organ that secretes six hormones from five different cell types. Given the fact that all distinct hormone producing cells arise from a common ectodermal primordium, the patterning, architecture and plasticity of the gland is impressive. Among the transcription factors involved in the early steps of pituitary organogenesis are SOX2 and SOX3, members of the SOX family that are emerging as key players in many developmental processes. Studies in vitro and in vivo in transgenic animal models have helped to elucidate their expression patterns and roles in the developing hypothalamo–pituitary region. It has been demonstrated that they may be involved in pituitary development either directly, through shaping of Rathke's pouch, or indirectly affecting signalling from the diencephalon. Their role has been further underlined by the pleiotropic effects of their mutations in humans that range from isolated hormone deficiencies to panhypopituitarism and developmental abnormalities affecting many organ systems. However, the exact mechanism of action of SOX proteins, their downstream targets and their interplay within the extensive network that regulates pituitary development is still the subject of a growing number of studies. The elucidation of their role is crucial for the understanding of a number of processes that range from developmental mechanisms to disease phenotypes and tumorigenesis.


2021 ◽  
Author(s):  
Xiao-jian Wang ◽  
Xiao Lu ◽  
Song-jia Guo ◽  
Wei Tian ◽  
Jian-bo Wu

Abstract Background: To observed the effect of autophagy in tibial growth plate chondrocytes on apoptosis in chronic renal insufficiency(CRI) rats.Method: Male 4-week-old Sprague Dawley(SD) rats were randomly divided into two groups (n=20/per group): (1) the normal group was intragastrically administered distilled water; and (2) the CRI group was given a 150 mg/(kg·d) adenine suspension. All rats were sacrificed after continuous gavage for 6 weeks. The tibial length and the width of the tibial growth plate were measured using micro-CT. The width of the tibial growth plate was also measured in histological sections at both 4 w and 10 w. The level of the autophagy marker Beclin-1 in chondrocytes was measured by immunofluorescence. The level of glycogenin-1, a marker of intracellular glycogen accumulation, was measured by immunohistochemistry in chondrocytes in vivo and in vitro. The apoptosis rate of chondrocytes was measured by the TUNEL method in vivo and in vitro.Results: The results showed that the length of tibia was shorter and the width of tibia growth plate was narrower in CRF young rats. Autophagy level of chondrocytes in tibial growth plate decreased, and accumulation of glycogen granules in chondrocytes increased significantly. Meanwhile, the apoptosis rate of chondrocytes in tibial growth plate increased.Conclusion: When CRF occurred in young rats, the autophagy level of chondrocytes in tibial growth plate decreased significantly.As a result, there are not enough autophagic vesicles to swallow glycogen granules in chondrocytes and degrade them into glucose for energy supply, which leads to chondrocyte apoptosis.Autophagy of chondrocytes is at least partly involved in energy metabolism of cells.


2019 ◽  
Author(s):  
Sichao Yang ◽  
Meng Zhang ◽  
Liqing Xu ◽  
Zhengrong Luo ◽  
Qinglin Zhang

AbstractPersimmon proanthocyanidin (PA) biosynthetic had been reported to be regulated by several transcription factors, but the miRNAs function involved in this process was poorly understood. We identified a miRNA858b that putatively targeted two R2R3-MYB transcription factors, DkMYB19/DkMYB20. Transcript accumulation of DkMYB19/DkMYB20 and miRNA858b showed contrasting divergent expression patterns during fruit development. DkMYB19/DkMYB20 were confirmed to be localized in the nucleus. The interaction between miRNA858b and DkMYB19/DkMYB20 were experimentally validated by 5’ RNA ligase-mediated RACE and LUC enzyme activity detection. Overexpression of miRNA858b led to the down-regulation of DkMYB19/DkMYB20 which reduced the accumulation of PA, whereas the reduced miRNA858b activity that up-regulated the DkMYB19/DkMYB20 resulted in high levels of PA in STTM858b transient expression in leaves in vivo. Similarly, the transient transformation of miRNA858b in fruit wafers in vitro also reduced the accumulation of PA by repressing the DkMYB19/DkMYB20, while the up-regulation of DkMYB19/DkMYB20 enhanced the accumulation of PA in STTM858b or DkMYB19/DkMYB20 transient transformation in fruit wafers. PA content decreased after overexpression of miRNA858b in Arabidopsis wild type and DkMYB19/DkMYB20 in persimmon leaf callus consisted with the above results. These findings suggested that miRNA858b repressed the expression of DkMYB19/DkMYB20 which contribute to PA accumulation in persimmon.


Development ◽  
1996 ◽  
Vol 122 (8) ◽  
pp. 2449-2464 ◽  
Author(s):  
Y. Nakagawa ◽  
T. Kaneko ◽  
T. Ogura ◽  
T. Suzuki ◽  
M. Torii ◽  
...  

Although a number of genes have been found to have restricted expression domains in the embryonic forebrain and midbrain, it remains largely unknown how the expression of these genes is regulated at the cellular level. In this study, we explored the mechanisms for the differential expression of region-specific transcription factors in neuroepithelial cells by using both primary and immortalized neuroepithelial cells from the rat brain at embryonic day 11.5. We found that differential expression patterns of Pax-3, Pax-5, Pax-6, Dlx-1, Dlx-2, Emx2, Otx1 and Dbx observed in vivo were maintained even when the cells were isolated and cultured in vitro, free from environmental influences. Furthermore, in response to Sonic hedgehog, which is a major inductive signal from the environment for regional specification, neuroepithelial cells that maintain distinct regional identities expressed different sets of ventral-specific genes including Islet-1, Nkx-2.1 and Nkx-2.2. These results suggest that certain cell-autonomous mechanisms play important roles in regulating both environmental signal-dependent and -independent expression of region-specific genes. Thus, we propose that use of the in vitro culture systems we describe in this study facilitates the understanding of regulatory mechanisms of region-specific genes in neuroepithelial cells.


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