• Biomolecules & Therapeutics
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• v.25 no.5
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• pp.504-510
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• 2017

Inhibitor of nuclear factor kappa-B kinase beta ($IKK{\beta}$) plays a critical role in cell proliferation and inflammation in various cells by activating $NF-{\kappa}B$ signaling. However, the interrelationship between peroxisome proliferator-activated receptor ${\alpha}$ ($PPAR{\alpha}$) and $IKK{\beta}$ in cell proliferation is not clear. In this study, we investigated the possible role of $PPAR{\alpha}$ in the hepatic cell death in the absence of $IKK{\beta}$ gene using liver-specific Ikkb-null ($Ikkb^{F/F-AlbCre}$) mice. To examine the function of $PPAR{\alpha}$ activation in hepatic cell death, wild-type ($Ikkb^{F/F}$) and $Ikkb^{F/F-AlbCre}$ mice were treated with $PPAR{\alpha}$ agonist Wy-14,643 (0.1% w/w chow diet) for two weeks. As a result of Wy-14,643 treatment, apoptotic markers including caspase-3 cleavage, poly (ADP-ribose) polymerase (PARP) cleavage and TUNEL-positive staining were significantly decreased in the $Ikkb^{F/F-AlbCre}$ mice. Surprisingly, Wy-14,643 increased the phosphorylation of p65 and STAT3 in both Ikkb and $Ikkb^{F/F-AlbCre}$ mice. Furthermore, BrdU-positive cells were significantly increased in both groups after treatment with Wy-14,643. Our results suggested that $IKK{\beta}-derived$ hepatic apoptosis could be altered by $PPAR{\alpha}$ activation in conjunction with activation of $NF-{\kappa}B$ and STAT3 signaling.

• The Korea Journal of Herbology
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• v.33 no.6
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• pp.35-42
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• 2018

Objectives : The aim of this study was to investigate whether the extract of Coptidis Rhizoma inhibits inflammation in chronic cold stress (CCS)-exposed mice or not. Methods : Coptidis Rhizoma extract (CRE) was made by reflux with distilled water. Male ICR mice (7 weeks old) were divided randomly into 5 groups: (1) control, (2) CCS, (3) CCS+CRE 100 mg/kg, (4) CCS+CRE 300 mg/kg, (5) CCS+CRE 1,000 mg/kg groups. Mice were orally administered once a day for 14 days starting from 1 day before CCS. Group (2)-(5) were exposed to CCS conditions that maintained at $4^{\circ}C$ for 2 h once a day for 14 days. The levels of serum cortisol and hypothalamic prostaglandin E1 (PGE1) and PGE2 were measured by enzyme-linked immunosorbent assay kit. The expression levels of several pro-inflammatory factors like heat shock protein 70 (HSP70), c-fos, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) were measured by western blot analysis in mouse hypothalamus. Results : Oral administration of CRE 1,000 mg/kg significantly suppressed the increase of serum cortisol levels in mice exposed to CCS. CCS-exposed mice had significantly increased the expression of HSP70, c-fos, and NF-kB in hypothalamus, while CRE treatment significantly attenuated the elevation of these pro-inflammatory factors. The ratio of PGE2/PGE1 was also higher in CCS-exposed mice than control group. CRE treatment significantly reduced the increase of PGE2/PGE1 ratio induced by CCS. Conclusion : These findings suggest that Coptidis Rhizoma may work as a potential agent to modulate inflammatory responses under the condition of cold adaptation formed by CCS.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.2
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• pp.73-81
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• 2013

Purpose: Smad4 is a central mediator for transforming growth factor-${\beta}$/bone morphogenetic protein ($TGF-{\beta}/BMP$) signals, which are involved in regulating cranial neural crest cell formation, migration, proliferation, and fate determination. Accumulated evidences indicate that $TGF-{\beta}/BMP$ signaling plays key roles in the early tooth morphogenesis. However, their roles in the late tooth formation, such as cellular differentiation and matrix formation are not clearly understood. The objective of this study is to understand the roles of Smad4 in vivo during enamel and dentin formation through tissue-specific inactivation of Smad4. Methods: We generated and analyzed mice with dental epithelium-specific inactivation of the Smad4 gene (K14-Cre:$Smad4^{fl/fl}$) and dental mesenchyme-specific inactivation of Smad4 gene (Osr2Ires-Cre:$Smad4^{fl/fl}$). Results: In the tooth germs of K14-Cre:$Smad4^{fl/fl}$, ameloblast differentiation was not detectable in inner enamel epithelial cells, however, dentin-like structure was formed in dental mesenchymal cells. In the tooth germs of Osr2Ires-Cre:$Smad4^{fl/fl}$ mice, ameloblasts were normally differentiated from inner enamel epithelial cells. Interestingly, we found that bone-like structures, with cellular inclusion, were formed in the dentin region of Osr2Ires-Cre:$Smad4^{fl/fl}$ mice. Conclusion: Taken together, our study demonstrates that Smad4 plays a crucial role in regulating ameloblast and odontoblast differentiation, as well as in regulating epithelial-mesenchymal interactions during tooth development.

• International Journal of Oral Biology
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• v.36 no.3
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• pp.135-141
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• 2011

Hertwig's epithelial root sheath (HERS) consists of bi-layered cells derived from the inner and outer dental epithelia and plays important roles in tooth root formation as well as in the maintenance and regeneration of periodontal tissues. With regards to the fate of HERS, and although previous reports have suggested that this entails the formation of epithelial rests of Malassez, apoptosis or an epithelial-mesenchymal transformation (EMT), it is unclear what changes occur in the epithelial cells in this structure. This study examined whether HERS cells undergo EMT using a keratin-14 (K14) cre:ROSA 26 transgenic reporter mouse. The K14 transgene is expressed by many epithelial tissues, including the oral epithelium and the enamel organ. A distinct K14 expression pattern was found in the continuous HERS bi-layer and the epithelial diaphragm were visualized by detecting the ${\beta}$-galactosidase (lacZ) activity in 1 week postnatal mice. The 2 and 4 week old mice showed a fragmented HERS with cell aggregation along the root surface. However, some of the lacZ-positive dissociated cells along the root surface were not positive for pan-cytokeratin. These results suggest that the K14 transgene is a valuable marker of HERS. In addition, the current data suggest that some of the HERS cells may lose their epithelial properties after fragmentation and subsequently undergo EMT.

• Molecules and Cells
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• v.38 no.5
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• pp.426-431
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• 2015

Odin has been implicated in the downstream signaling pathway of receptor tyrosine kinases, such as the epidermal growth factor and Eph receptors. However, the physiologically relevant function of Odin needs to be further determined. In this study, we used Odin heterozygous mice to analyze the Odin expression pattern; the targeted allele contained a ${\beta}$-geo gene trap vector inserted into the 14t intron of the Odin gene. Interestingly, we found that Odin was exclusively expressed in ependymal cells along the brain ventricles. In particular, Odin was highly expressed in the subcommissural organ, a small ependymal glandular tissue. However, we did not observe any morphological abnormalities in the brain ventricles or ependymal cells of Odin null-mutant mice. We also generated BAC transgenic mice that expressed the PTB-deleted Odin (dPTB) after a floxed GFP-STOP cassette was excised by tissue-specific Cre expression. Strikingly, Odin-dPTB expression played a causative role in the development of the hydrocephalic phenotype, primarily in the midbrain. In addition, Odin-dPTB expression disrupted proper development of the subcommissural organ and interfered with ependymal cell maturation in the cerebral aqueduct. Taken together, our findings strongly suggest that Odin plays a role in the differentiation of ependymal cells during early postnatal brain development.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.6
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• pp.460-465
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• 2010

Introduction: A cleft palate is a common birth defect in humans with an incidence of 1/500 to 1/1,000 births. It appears to be caused by multiple genetic and environmental factors during palatogenesis. Many molecules are involved in palate formation but the biological mechanisms underlying the normal palate formation and cleft palate are unclear. Accumulating evidence suggests that transforming growth factor $\beta$/bone morphogenetic proteins (TGF-$\beta$/BMP) family members mediate the epithelial-mesenchymal interactions during palate formation. However, their roles in palatal morphogenesis are not completely understood. Materials and Methods: To understand the roles of TGF-$\beta$/BMP signaling in vivo during palatogenesis, mice with a palatal mesenchyme- specific deletion of Smad4, a key intracellular mediator of TGF-$\beta$/BMP signaling, were generated and analyzed using the Osr2Ires-Cre mice. Results: The mutant mice were alive at the time of birth with open eyelids and complete cleft palate but died within 24 hours after birth. In skeletal preparation, the horizontal processes of the palatine bones in mutants were not formed and resulted in a complete cleft palate. At E13.5, the palatal shelves of the mutants were growing as normally as those of theirwild type littermates. However, the palatal shelves of the mutants were not elevated at E14.5 in contrast to the elevated palatal shelves of the wild type mice. At E15.5, the palatal shelves of the mutants were elevated over the tongue but did not come in contact with each other, resulting in a cleft palate. Conclusion: These results suggest that mesenchymal Smad4 mediated signaling is essential for the growth of palatal processes and suggests that TGF-$\beta$/BMP family members are essential regulators during palate development.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.1827-1831
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• 2015

Background: We generated a mouse model of prostate cancer based on the adult-prostate-specific inactivation of phosphatase and tensin homolog (PTEN) using the Cre-loxP system. The potential of our mice as a useful animal model was examined by evaluating the chemopreventive efficacy of the anti-androgen, chlormadinone acetate (CMA). Materials and Methods: Six-week-old mice were treated subcutaneously with $50{\mu}g/g$ of CMA three times a week for 9 or 14 weeks and sacrificed at weeks 15 and 20. Macroscopic change of the entire genitourinary tract (GUT) and histologically evident prostate gland tumor development were evaluated. Proliferation and apoptosis status in the prostate were examined by immunohistochemistry. Results: CMA triggered significant shrinkage of not only the GUT but also prostate glands at 15 weeks compared to the control (p=0.017 and p=0.010, respectively), and the trend became more marked after a further five-weeks of treatment. The onset of prostate adenocarcinoma was not prevented but the proliferation of cancer cells was inhibited by CMA, which suggested the androgen axis is critical for cancer growth in these mice. Conclusions: Conditional PTEN-deficient mice are useful as a preclinical model for chemoprevention studies and serve as a valuable tool for the future screening of potential chemopreventive agents.

• Clinical and Experimental Reproductive Medicine
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• v.43 no.1
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• pp.9-14
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• 2016

Objective: Autophagy contributes to the clearance and recycling of macromolecules and organelles in response to stress. We previously reported that vitrified mouse oocytes show acute increases in autophagy during warming. Herein, we investigate the potential role of Atg7 in oocyte vitrification by using an oocyte-specific deletion model of the Atg7 gene, a crucial upstream gene in the autophagic pathway. Methods: Oocyte-specific Atg7 deficient mice were generated by crossing Atg7 floxed mice and Zp3-Cre transgenic mice. The oocytes were vitrified-warmed and then subjected to in vitro fertilization and development. The rates of survival, fertilization, and development were assessed in the Atg7 deficient oocytes in comparison with the wildtype oocytes. Light chain 3 (LC3) immunofluorescence staining was performed to determine whether this method effectively evaluates the autophagy status of oocytes. Results: The survival rate of vitrified-warmed $Atg7^{f/f}$;Zp3-Cre ($Atg7^{d/d}$) metaphase II (MII) oocytes was not significantly different from that of the wildtype ($Atg7^{f/f}$) oocytes. Fertilization and development in the $Atg7^{d/d}$ oocytes were significantly lower than the $Atg7^{f/f}$ oocytes, comparable to the $Atg5^{d/d}$ oocytes previously described. Notably, the developmental rate improved slightly in vitrified-warmed $Atg7^{d/d}$ MII oocytes when compared to fresh $Atg7^{d/d}$ oocytes. LC3 immunofluorescence staining showed that this method can be reliably used to assess autophagic activation in oocytes. Conclusion: We confirmed that the LC3-positive signal is nearly absent in $Atg7^{d/d}$ oocytes. While autophagy is induced during the warming process after vitrification of MII oocytes, the Atg7 gene is not essential for survival of vitrified-warmed oocytes. Thus, induction of autophagy during warming of vitrified MII oocytes seems to be a natural response to manage cold or other cellular stresses.