Peroxisome Proliferator-Activated Receptor α Facilitates Osteogenic Differentiation in MC3T3-E1 Cells via the Sirtuin 1-Dependent Signaling Pathway

Kai Gong,Bo Qu,Cairu Wang,Jingsong Zhou,Dongfa Liao,Wei Zheng,Xianming Pan 한국분자세포생물학회 2017 Molecules and cells Vol.40 No.6

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by lack of insulin and high glucose levels. T2DM can cause bone loss and fracture, thus leading to diabetic osteoporosis. Promoting osteogenic differentiation of osteoblasts may effectively treat diabetic osteoporosis. We previously reported that Sirtuin 1 (Sirt1), a NAD+-dependent deacetylase, promotes osteogenic differentiation through downregulation of peroxisome proliferator-activated receptor (PPAR) γ. We also found that miR-132 regulates osteogenic differentiation by downregulating Sirt1 in a PPAR /δ-dependent manner. The ligand-activated transcription factor, PPAR , is another isotype of the peroxisome proliferator-activated receptor family that helps maintain bone homeostasis and promot bone formation. Whether the regulatory role of PPAR in osteogenic differentiation is mediated via Sirt1 remains unclear. In the present study, we aimed to de-termine this role and the underlying mechanism by using high glucose (HG) and free fatty acids (FFA) to mimic T2DM in MC3T3-E1 cells. The results showed that HG-FFA significantly inhibited expression of PPAR , Sirt1 and osteogenic differentiation, but these effects were markedly reversed by PPAR overexpression. Moreover, siSirt1 attenuated the positive effects of PPAR on osteogenic differentiation, suggesting that PPAR promotes osteogenic differentiation in a Sirt1-dependent manner. Luciferase activity assay confirmed interactions between PPAR and Sirt1. These findings indicate that PPAR promotes osteogenic differentiation via the Sirt1-dependent signaling pathway.

Peroxisome Proliferator-Activated Receptor α Facilitates Osteogenic Differentiation in MC3T3-E1 Cells via the Sirtuin 1-Dependent Signaling Pathway

Gong, Kai,Qu, Bo,Wang, Cairu,Zhou, Jingsong,Liao, Dongfa,Zheng, Wei,Pan, Xianming Korean Society for Molecular and Cellular Biology 2017 Molecules and cells Vol.40 No.6

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by lack of insulin and high glucose levels. T2DM can cause bone loss and fracture, thus leading to diabetic osteoporosis. Promoting osteogenic differentiation of osteoblasts may effectively treat diabetic osteoporosis. We previously reported that Sirtuin 1 (Sirt1), a $NAD^+$-dependent deacetylase, promotes osteogenic differentiation through downregulation of peroxisome proliferator-activated receptor (PPAR) ${\gamma}$. We also found that miR-132 regulates osteogenic differentiation by downregulating Sirt1 in a $PPAR{\beta}/{\delta}$-dependent manner. The ligand-activated transcription factor, $PPAR{\alpha}$, is another isotype of the peroxisome proliferator-activated receptor family that helps maintain bone homeostasis and promot bone formation. Whether the regulatory role of $PPAR{\alpha}$ in osteogenic differentiation is mediated via Sirt1 remains unclear. In the present study, we aimed to determine this role and the underlying mechanism by using high glucose (HG) and free fatty acids (FFA) to mimic T2DM in MC3T3-E1 cells. The results showed that HG-FFA significantly inhibited expression of $PPAR{\alpha}$, Sirt1 and osteogenic differentiation, but these effects were markedly reversed by $PPAR{\alpha}$ overexpression. Moreover, siSirt1 attenuated the positive effects of $PPAR{\alpha}$ on osteogenic differentiation, suggesting that $PPAR{\alpha}$ promotes osteogenic differentiation in a Sirt1-dependent manner. Luciferase activity assay confirmed interactions between $PPAR{\alpha}$ and Sirt1. These findings indicate that $PPAR{\alpha}$ promotes osteogenic differentiation via the Sirt1-dependent signaling pathway.

Accumulation of Pax2 transactivation domain interaction protein (PTIP) at sites of DNA breaks via RNF8-dependent pathway is required for cell survival after DNA damage.

Gong, Zihua,Cho, Young-Wook,Kim, Ja-Eun,Ge, Kai,Chen, Junjie American Society for Biochemistry and Molecular Bi 2009 The Journal of biological chemistry Vol.284 No.11

<P>Genomic stability in eukaryotic cells is maintained by the coordination of multiple cellular events including cell cycle checkpoint, DNA repair, transcription, and apoptosis after DNA damage. Pax2 transactivation domain interaction protein (PTIP), a protein that contains six BRCT domains, has been implicated in DNA damage response. In this study we showed that recruitment of PTIP to damaged chromatin depends on DNA damage signaling proteins gammaH2AX.MDC1.RNF8, which in turn facilitates sustained localization of PA1 (PTIP-associated protein 1) to sites of DNA break. Similar to PTIP, depletion of PA1 increases cellular sensitivity to ionizing radiation. Furthermore, we demonstrated that the N-terminal PA1 binding domain and the C-terminal focus-localization domain of PTIP are critical for PTIP function in DNA damage repair. Interestingly, although PTIP and PA1 associate with MLL (mixed lineage leukemia) complexes and participate in transcriptional regulation, this function of PTIP.PA1 in DNA damage response is likely to be independent of the MLL complexes. Taken together, we propose that a subset of PTIP.PA1 complex is recruited to DNA damage sites via the RNF8-dependent pathway and is required for cell survival in response to DNA damage.</P>

Efficient Expression of Glucagon-like Peptide-1 Analogue with Human Serum Albumin Fusion Protein in Pichia pastoris Using the Glyceraldehyde-3-phosphate Dehydrogenase Promoter

Kai Qian,XiaoHai Gong,Bo Guan,SuPing Wu,JingJing Zhang,Jing Qian,YanFei Cai,Yun Chen,ZuoYing Duan,Xin Ma,HuaZhong Li,Jian Jin 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.4

Glucagon-like peptide-1 (GLP-1) was a potential therapeutic drug for type II diabetes, mainly because of the stimulatory effect on insulin secretion under condition of high blood glucose. We used PCR to obtain a recombination gene, GGH, in which two GLP-1 (GLP-1A2G) mutants were connected in series and then fused to the N terminal of human serum albumin. The fusion gene was inserted into pGAPZaA plasmid with Saccharomyces cerevisiae α- factor secretion signal sequence, and was expressed by the glyceraldehyde-3-phosphate dehydrogenase (GAP) promoter. The engineered strain was constructed by integrating the recombinant plasmid pGAPZαA/GGH into the genome of Pichia pastoris GS115. Genome PCR and western blot showed that the recombinant P. pastoris successfully expressed the fusion protein GGH. The yield of GGH reached 78 mg/L after 72 h fermentation in a flask, using glucose as the optimal carbon source. Fed-batch fermentation was investigated in a 5 L bioreactor, and the expression level of GGH reached 246 mg/L in 52 h. The fusion protein GGH was purified in four steps, and the final purity was 96.1%. The in vitro bioactivity of GGH was the same as that expressed in P. pastoris by the AOX1 promoter. This study described an efficient way to express GGH fusion protein in P. pastoris using GAP promoter, fermentation was easier to control without carbon source change and fermentation time was 20 h less than AOX1 promotercontrolled GGH fermentation.

The basic helix–loop–helix transcription factors in the Colorado potato beetle Leptinotarsa decemlineata

Kai-Yun Fu,Qing-Wei Meng,Feng-Gong Lüa,Wen-Chao Guo,Tursun Ahmat,Guo-Qing Li 한국응용곤충학회 2015 Journal of Asia-Pacific Entomology Vol.18 No.2

The basic helix–loop–helix (bHLH) transcription factors possess crucial functions in cell proliferation, determination, differentiation, cell cycle maintenance and homeostasis or stress response pathways. Since a few juvenile hormone analogues such as hydroprene, methoprene and pyriproxyfen targeting a bHLH member Met are already registered for pest management, there is a potential to develop more insecticides targeting various bHLHs. The identification of bHLH members is the first step. Based on the transcriptome and the genome of the Colorado potato beetle Leptinotarsa decemlineata, the most important pest in potato, 49 bHLH members were identified. All LdbHLH memberswere defined by their names and families according to various phylogenetic analyses with bHLH homologues of Drosophila melanogaster, Apis mellifera, Bombyx mori and Tribolium castaneum. Among these LdbHLHs, 17, 10, 10, 1, 10 and 1 members belonged to A, B, C, D, E and F high-order groups, respectively. The results would provide useful background information for future studies on functions of bHLH proteins in the regulation of L. decemlineata development. Moreover, the bHLHs could serve as potential insecticide targets. These proteins could be used in small molecule screen, or in the development of RNAi-based pest management methods.

An Optimized Hierarchical Handoff Method with Mobile IP and SIP

Kai Zhang(장개),Ji-Gong(공길),Yoonhwan Park(박윤환),Kisung Yu(유기성),Gihwan Cho(조기환) 한국멀티미디어학회 2008 한국멀티미디어학회 학술발표논문집 Vol.2008 No.1

In the 4 generation(4G) wireless network, mobility management can be effectively achieved by applying Mobile IP(MIP) and the Session Initiation Protocol(SIP) in cooperatively. However, an important and challenging issue is the handoff management in this architecture. In this paper, we present an optimized handoff method with MIP and SIP. Two mechanisms are proposed to resolve micro-mobility, along with same domain mobility. Micro-mobility handoff manages movements in the one area, while same domain mobility handoff manages movements between two neighboring are as. This method makes use of a retransmission for micro-mobility, and multicasting to re-establish a traffic flow for same domain mobility.

Biological Characteristics of Recombinant Arthrobotrys oligospora Chitinase AO-801

Gong, Shasha,Meng, Qingling,Qiao, Jun,Huang, Yunfu,Zhong, Wenqiang,Zhang, Guowu,Zhang, Kai,Li, Ningxing,Shang, Yunxia,Li, Zhiyuan,Cai, Xuepeng The Korea Society for Parasitology and Tropical Me 2022 The Korean Journal of Parasitology Vol.60 No.5

Chitinase AO-801 is a hydrolase secreted by Arthrobotrys oligospora during nematode feeding, while its role remained elusive. This study analyzed the molecular characteristics of recombinant chitinase of Arthrobotrys oligospora (reAO-801). AO-801 belongs to the typical glycoside hydrolase 18 family with conserved chitinase sequence and tertiary structure of (α/β)₈ triose-phosphate isomerase (TIM) barrel. The molecular weight of reAO-801 was 42 kDa. reAO-801 effectively degraded colloidal and powdered chitin, egg lysate, and stage I larval lysate of Caenorhabditis elegans. The activity of reAO-801 reached its peak at 40℃ and pH values between 4-7. Enzyme activity was inhibited by Zn2⁺, Ca2⁺, and Fe3⁺, whereas Mg2⁺ and K⁺ potentiated its activity. In addition, urea, sodium dodecyl sulfate, and 2-mercaptoethanol significantly inhibited enzyme activity. reAO-801 showed complete nematicidal activity against C. elegans stage I larvae. reAO-801 broke down the C. elegans egg shells, causing them to die or die prematurely by hatching the eggs. It also invoked degradation of Haemonchus contortus eggs, resulting in apparent changes in the morphological structure. This study demonstrated the cytotoxic effect of reAO-801, which laid the foundation for further dissecting the mechanism of nematode infestation by A. oligospora.

Long Noncoding RNA PVT1 Promotes Stemness and Temozolomide Resistance through miR-365/ELF4/SOX2 Axis in Glioma

Gong Rui,Li Zhi-Qiang,Fu Kai,Ma Chao,Wang Wei,Chen Jin-Cao 한국뇌신경과학회 2021 Experimental Neurobiology Vol.30 No.3

Long non-coding RNA (lncRNA) are a class of non-coding RNAs demonstrated to play pivotal roles in regulating tumor progression. Therefore, deciphering the regulatory role of lncRNA in the development of glioma may offer a promising therapeutic target for treatment of glioma. We performed RT-qPCR analysis on the expression of lncRNA plasmacytoma variant translocation 1 (PVT1) and miR-365 in glioma tissues and cell lines. Cell proliferation and viability was assessed with CCK8 assay. Cell migration was assessed by wound healing assay. Transwell assay was used to assess cell invasion capacity. Expression of CD133+ cells was detected by flow cytometry. Western blot assay was used to detection the expression of ELF4 and stemness-related protein SOX2, Oct4 and Nanog. Bioinformatics and dual-luciferase assay were used to predict and validate the interaction between PVT1 and miR-365. Elevated PVT1 expression was observed in glioma tissues and cells. Knockdown of PVT1 and overexpression of miR-365 inhibited proliferation, migration, invasion and promoted stemness and Temozolomide (TMZ) resistance of glioma cells. PVT1 regulated ELF4 expression by competitively binds to miR-365. PVT1 regulated the stemness and sensitivity of TMZ of glioma cells through miR-365/ELF4/ SOX2 axis. This study identified that PVT1 promoted glioma stemness through miR-365/ELF4/SOX2 axis.

Structural Deformation Sensing Based on Distributed Optical Fiber Monitoring Technology and Neural Network

Gong-Yu Hou,Zi-Xiang Li,Kai-Di Wang,Jin-Xin Hu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11

Structural deformation monitoring is vital to the safety of concrete structures. However, the distributed deformation of structures cannot be easily obtained using existing monitoring methods in civil engineering. To this end, this paper proposes a method to estimate the continuous deformation of concrete beams by utilizing the distributed optical fiber monitoring technology. In this method, optical fibers and a total station are used to obtain the strain and deformation distribution curves of a concrete beam, respectively. Subsequently, these curves are inputted to a back propagation network as training samples to learn their relationships. The results show that the deformation value of trained neural network is very close to that of the total station, with a maximum error of only 2.7% (0.3 mm). The linear regression analysis shows a goodness of fit R2 greater than 0.98, which confirms the reliability of the simulations results.

An Energy and Coverage Efficient Clustering Method for Wireless Sensor Network

공지(Ji Gong),장개(Kai Zhang),김승해(SeungHae Kim),조기환(Gihwan Cho) 한국정보과학회 2008 한국정보과학회 학술발표논문집 Vol.35 No.1

Due to technological advances, the manufacturing of small and low cost of sensors becomes technically and economically feasible. In recent years, an increasing interest in using Wireless Sensor Network (WSN) in various applications, including large scale environment monitoring, battle field surveillance, security management and location tracking. In these applications, hundreds of sensor nodes are left to be unattended to report monitored data to users. Since sensor nodes are placed randomly and sometimes are deployed in underwater. It is impossible to replace batteries often when batteries run out. Therefore, reducing energy consumption is the most important design consideration for sensor networks.