• The Korean Journal of Physiology and Pharmacology
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• 제20권5호
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• pp.459-466
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• 2016

Adipogenic differentiation of mesenchymal stem cells (MSCs) is critical for metabolic homeostasis and nutrient signaling during development. However, limited information is available on the pivotal modulators of adipogenic differentiation of MSCs. Adaptor protein Lnk (Src homology 2B3 [SH2B3]), which belongs to a family of SH2-containing proteins, modulates the bioactivities of different stem cells, including hematopoietic stem cells and endothelial progenitor cells. In this study, we investigated whether an interaction between insulin-like growth factor-1 receptor (IGF-1R) and Lnk regulated IGF-1-induced adipogenic differentiation of MSCs. We found that wild-type MSCs showed greater adipogenic differentiation potential than $Lnk^{-/-}$ MSCs. An ex vivo adipogenic differentiation assay showed that $Lnk^{-/-}$ MSCs had decreased adipogenic differentiation potential compared with wild-type MSCs. Interestingly, we found that Lnk formed a complex with IGF-1R and that IGF-1 induced the dissociation of this complex. In addition, we observed that IGF-1-induced increase in the phosphorylation of Akt and mammalian target of rapamycin was triggered by the dissociation of the IGF-1R-Lnk complex. Expression levels of a pivotal transcription factor peroxisome proliferator-activated receptor gamma ($PPAR-{\gamma}$) and its adipogenic target genes (LPL and FABP4) significantly decreased in $Lnk^{-/-}$ MSCs. These results suggested that Lnk adaptor protein regulated the adipogenesis of MSCs through the $IGF-1/Akt/PPAR-{\gamma}$ pathway.

• The Korean Journal of Physiology and Pharmacology
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• 제24권5호
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• pp.423-431
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• 2020

This study aimed to evaluate the effect of curcumin on brain hypoxic-ischemic (HI) damage in neonatal rats and whether the phosphoinositide 3-kinase (PI3K)/Akt/vascular endothelial growth factor (VEGF) signaling pathway is involved. Brain HI damage models were established in neonatal rats, which received the following treatments: curcumin by intraperitoneal injection before injury, insulin-like growth factor 1 (IGF-1) by subcutaneous injection after injury, and VEGF by intracerebroventricular injection after injury. This was followed by neurological evaluation, hemodynamic measurements, histopathological assessment, TUNEL assay, flow cytometry, and western blotting to assess the expression of p-PI3K, PI3K, p-Akt, Akt, and VEGF. Compared with rats that underwent sham operation, rats with brain HI damage showed remarkably increased neurological deficits, reduced right blood flow volume, elevated blood viscosity and haematocrit, and aggravated cell damage and apoptosis; these injuries were significantly improved by curcumin pretreatment. Meanwhile, brain HI damage induced the overexpression of p-PI3K, p-Akt, and VEGF, while curcumin pretreatment inhibited the expression of these proteins. In addition, IGF-1 treatment rescued the curcumin-induced down-regulated expression of p-PI3K, p-Akt, and VEGF, and VEGF overexpression counteracted the inhibitory effect of curcumin on brain HI damage. Overall, pretreatment with curcumin protected against brain HI damage by targeting VEGF via the PI3K/Akt signaling pathway in neonatal rats.

• Reproductive and Developmental Biology
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• 제38권1호
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• pp.21-34
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• 2014

The majority of early embryonic mortality in pregnancy occurs during the peri-implantation stage, suggesting that this period is important for conceptus viability and the establishment of pregnancy. Successful establishment of pregnancy in all mammalian species depends on the orchestrated molecular events that transpire at the conceptus-uterine interface during the peri-implantation period. This maternal-conceptus interaction is especially crucial in pigs because in them non-invasive epitheliochorial placentation occurs, in which the pre-implantation phase is prolonged. During the pre-implantation period, conceptus survival and the establishment of pregnancy are known to depend on the developing conceptus receiving an adequate supply of histotroph, which contains a wide range of nutrients and growth factors. Evidence links growth factors including epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), vascular endothelial growth factor (VEGF), and colony-stimulating factor 2 (CSF2) to embryogenesis or implantation in various mammalian species; however, in the case of pig, little is known about such functions of these growth factors, especially their regulatory mechanisms at the maternal-conceptus interface. Our research group has presented evidence for promising growth factors affecting cellular activities of primary porcine trophectoderm (pTr) cells, and we have identified potential intracellular signaling pathways responsible for the activities induced by these factors. Therefore, this review focuses on promising growth factors at the maternal-conceptus interface regulating the development of the porcine conceptus and playing pivotal roles in implantation events during early pregnancy in pigs.

• Molecules and Cells
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• 제44권7호
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• pp.425-432
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• 2021

Aging is associated with functional and structural declines in organisms over time. Organisms as diverse as the nematode Caenorhabditis elegans and mammals share signaling pathways that regulate aging and lifespan. In this review, we discuss recent combinatorial approach to aging research employing C. elegans and mammalian systems that have contributed to our understanding of evolutionarily conserved aging-regulating pathways. The topics covered here include insulin/IGF-1, mechanistic target of rapamycin (mTOR), and sirtuin signaling pathways; dietary restriction; autophagy; mitochondria; and the nervous system. A combinatorial approach employing high-throughput, rapid C. elegans systems, and human model mammalian systems is likely to continue providing mechanistic insights into aging biology and will help develop therapeutics against age-associated disorders.

• Asian Pacific Journal of Cancer Prevention
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• 제17권8호
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• pp.3963-3969
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• 2016

Purpose:To assess IGFBP-6 expression in relation with the presence of the metabolic syndrome, adiponectin receptors (AdipoR1 and AdipoR2) and IGF-IR levels in colorectal adenocarcinoma cases. Materials and Methods: IGFBP-6 mRNA and protein levels were analyzed using real-time quantitative PCR and Western blotting in 46 patients. ELISA and flow cytometry were used for evaluation of AdipoR1, AdipoR2 and IGF-IR. Results: The results showed that IGFBP-6 mRNA expression and the IGFBP-6 content were higher in tumor tissue samples of colorectal cancer patients with tahtn without metabolic syndrome. In addition, the IGFBP-6 mRNA expression was associated with tumor invasion (tumor size) and the IGFBP-6 protein level was associated with nodal status. Positive correlations and positive nonlinear relations were found between the IGFBP-6 level and the AdipoR1 and AdipoR2 contents in colorectal cancer patients. Conclusions: The IGFBP-6 mRNA level and protein level were found to be associated with presence of metabolic syndrome. Positive correlations indicated probable cross-talk between the IGF-IR-mediated and adiponectin-mediated signaling pathways in colorectal carcinomas. IGFBP-6 may be considered as a potential biomarker associated with lymphogenous metastasis and the metabolic syndrome in colorectal cancer.

• BMB Reports
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• 제52권1호
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• pp.24-34
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• 2019

Sirtuin is an essential factor that delays cellular senescence and extends the organismal lifespan through the regulation of diverse cellular processes. Suppression of cellular senescence by Sirtuin is mainly mediated through delaying the age-related telomere attrition, sustaining genome integrity and promotion of DNA damage repair. In addition, Sirtuin modulates the organismal lifespan by interacting with several lifespan regulating signaling pathways including insulin/IGF-1 signaling pathway, AMP-activated protein kinase, and forkhead box O. Although still controversial, it is suggested that the prolongevity effect of Sirtuin is dependent with the level of and with the tissue expression of Sirtuin. Since Sirtuin is also believed to mediate the prolongevity effect of calorie restriction, activators of Sirtuin have attracted the attention of researchers to develop therapeutics for age-related diseases. Resveratrol, a phytochemical rich in the skin of red grapes and wine, has been actively investigated to activate Sirtuin activity with consequent beneficial effects on aging. This article reviews the evidences and controversies regarding the roles of Sirtuin on cellular senescence and lifespan extension, and summarizes the activators of Sirtuin including Sirtuin-activating compounds and compounds that increase the cellular level of nicotinamide dinucleotide.

• Experimental and Molecular Medicine
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• 제50권12호
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• pp.3.1-3.14
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• 2018

Type 1 diabetes mellitus (T1DM) is a pathological condition associated with osteopenia. $WNT/{\beta}$-catenin signaling is implicated in this process. Trabecular and cortical bone respond differently to $WNT/{\beta}$-catenin signaling in healthy mice. We investigated whether this signaling has different effects on trabecular and cortical bone in T1DM. We first established a streptozotocin-induced T1DM mouse model and then constitutively activated ${\beta}$-catenin in osteoblasts in the setting of T1DM (T1-CA). The extent of bone loss was greater in trabecular bone than that in cortical bone in T1DM mice, and this difference was consistent with the reduction in the expression of ${\beta}$-catenin signaling in the two bone compartments. Further experiments demonstrated that in T1DM mice, trabecular bone showed lower levels of insulin-like growth factor-1 receptor (IGF-1R) than the levels in cortical bone, leading to lower $WNT/{\beta}$-catenin signaling activity through the inhibition of the IGF-1R/Akt/glycogen synthase kinase $3{\beta}$ ($GSK3{\beta}$) pathway. After ${\beta}$-catenin was activated in T1-CA mice, the bone mass and bone strength increased to substantially greater extents in trabecular bone than those in cortical bone. In addition, the cortical bone of the T1-CA mice displayed an unexpected increase in bone porosity, with increased bone resorption. The downregulated expression of WNT16 might be responsible for these cortical bone changes. In conclusion, we found that although the activation of $WNT/{\beta}$-catenin signaling increased the trabecular bone mass and bone strength in T1DM mice, it also increased the cortical bone porosity, impairing the bone strength. These findings should be considered in the future treatment of T1DM-related osteopenia.

• Journal of Nutrition and Health
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• 제55권1호
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• pp.47-58
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• 2022

Purpose: Obesity and a high-fat diet (HFD) are risk factors for colorectal cancer. We have previously shown that luteolin (LUT) supplementation in HFD-fed mice markedly inhibits tumor development in chemically induced colon carcinogenesis. In this study, we evaluated the anticancer effect of LUT in the inhibition of cell proliferation in HFD-fed obese mice and HT-29 human colorectal adenocarcinoma cells grown in an adipocyte-derived medium. Methods: C57BL/6 mice were fed a normal diet (ND, 11.69% fat out of total calories consumed, n = 10), HFD (40% fat out of total calories consumed, n = 10), HFD with 0.0025% LUT (n = 10), and HFD with 0.005% LUT (n = 10) and were subjected to azoxymethane-dextran sulfate sodium chemical colon carcinogenesis. All mice were fed the experimental diet for 11 weeks. 3T3-L1 preadipocytes and HT-29 cells were treated with various doses of LUT in an adipocyte-conditioned medium (Ad-CM). Results: The weekly body weight changes in the LUT groups were similar to those in the HFD group; however, the survival rates of the LUT group were higher than those of the HFD group. Impaired crypt integrity of the colonic mucosa in the HFD group was observed to be restored in the LUT group. The colonic expression of proliferating cell nuclear antigen and insulin-like growth factor 1 (IGF-1) receptors were suppressed by the LUT supplementation in the HFD-fed mice. The LUT treatment (10, 20, and 40 µM) inhibited the proliferation and migration of HT-29 cells cultured in Ad-CM in a dose-dependent manner, as well as the differentiation of 3T3-L1 preadipocytes. Conclusion: These results suggest that the anticancer effect of LUT is probably due to the inhibition of IGF-1 signaling and adipogenesis-related cell proliferation in colon cancer cells.

• Asian-Australasian Journal of Animal Sciences
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• 제31권5호
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• pp.650-657
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• 2018

Objective: The study investigated the biological functions and mechanisms for controlling cashmere growth of Liaoning cashmere goat by ovarian carcinoma immunoreactive antigen-like protein 2 (OCIAD2) and decorin (DCN) genes. Methods: cDNA library of Liaoning cashmere goat was constructed in early stages. OCIAD2 and DCN genes related to cashmere growth were identified by homology analysis comparison. The expression location of OCIAD2 and DCN genes in primary and secondary hair follicles (SF) was performed using in situ hybridization. The expression of OCIAD2 and DCN genes in primary and SF was performed using real-time polymerase chain reaction (PCR). Results: In situ hybridization revealed that OCIAD2 and DCN were expressed in the inner root sheath of Liaoning cashmere goat hair follicles. Real-time quantitative PCR showed that these genes were highly expressed in SF during anagen, while these genes were highly expressed in primary hair follicle in catagen phase. Melatonin (MT) inhibited the expression of OCIAD2 and promoted the expression of DCN. Insulin-like growth factors-1 (IGF-1) inhibited the expression of OCIAD2 and DCN, while fibroblast growth factors 5 (FGF5) promoted the expression of these genes. MT and IGF-1 promoted OCIAD2 synergistically, while MT and FGF5 inhibited the genes simultaneously. MT+IGF-1/MT+FGF5 inhibited DCN gene. RNAi technology showed that OCIAD2 expression was promoted, while that of DCN was inhibited. Conclusion: Activation of bone morphogenetic protein (BMP) signaling pathway up-regulated OCIAD2 expression and stimulated SF to control cell proliferation. DCN gene affected hair follicle morphogenesis and periodic changes by promoting transforming growth $factor-{\beta}$ ($TGF-{\beta}$) and BMP signaling pathways. OCIAD2 and DCN genes have opposite effects on $TGF-{\beta}$ signaling pathway and inhibit each other to affect the hair growth.

• Animal Bioscience
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• 제36권6호
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• pp.920-928
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• 2023

Objective: Angora rabbits fed a low-protein diet exhibit decreased hair production performance. This study was set out to evaluate the effects of methionine on hair properties and nitrogen metabolism in Angora rabbits fed a low-protein diet and to investigate the gene expression related to hair follicle development to determine the possible molecular mechanism of methionine effects on hair follicle development. Methods: An experiment was conducted to investigate the effects of DL-methionine addition on a low-protein diet on hair development in Angora rabbits. Angora rabbits were divided into 5 groups: fed a normal diet (control), fed a low-protein diet (LP), or fed an LP supplemented with 0.2%, 0.4%, or 0.6% DL-methionine (Met). Results: The results showed that rabbits in the LP group had lower wool yield than the control rabbits, but the addition of 0.4% to 0.6% Met to LP attenuated these effects (p<0.05). Dietary addition of 0.4% to 0.6% Met to LP increased the apparent nitrogen digestibility, nitrogen utilization rate, and feed efficiency (p<0.05). Feeding LP decreased the insulin-like growth factor 1 (IGF1), keratin-associated protein (KAP) 3.1, and KAP 6.1 mRNA levels compared with the control, but the addition of 0.4% Met in LP attenuated these effects (p<0.05). Relative to the LP or control group, dietary addition of 0.4% Met increased versican mRNA levels. Conclusion: In conclusion, the addition of Met to LP could improves wool production performance and feed efficiency and reduce nitrogen emissions in Angora rabbits. Met can promote hair follicle development, which may be associated with IGF1, KAP, and the versican signaling.