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Preantral follicle growth is regulated by c-Jun-N-terminal kinase (JNK) pathway.

ABSTRACT: c-Jun N-terminal kinase (JNK) pathway has been shown to be essential for cell cycle progression and mitosis. We previously showed that this pathway is activated in mitotic granulosa cells of follicles from transitional to antral stages. In this study, we, therefore, aimed to investigate whether this signaling pathway has any effect on in-vitro growth of murine preantral follicles and granulosa cell cycle control. Two structurally different pharmacologic JNK inhibitors, SP600125 and AS601245, were used in the experiments. First their inhibitory concentrations were determined in granulosa cells by Western blot analysis. Then preantral follicles isolated from immature and adult C57BL/6 mice were cultured in matrigel and standard culture plates for 6 days with these inhibitors. Spontaneously immortalized rat granulosa cells (SIGCs) were first synchronized at G1/S and G2/M stages of cell cycle and then treated with JNK inhibitors. Cell cycle progression was analyzed with Bromodeoxyuridine (BrdU) assay and flow cytometry analysis. Both inhibitors significantly inhibited phosphorylation of c-Jun in granulosa cells at 25, 50, and 100 ?mol/L concentrations. Isolated preantral follicles cultured with these inhibitors exhibited arrested growth in culture in a dose-dependent manner. Cell cycle analyses showed that both inhibitors impair the progression of cell cycle at S phase and G2/M transition of granulosa cells. These results suggest that JNK pathway is essential for in vitro growth of preantral follicle growth and regulates both S phase and G2/M stages of cell cycle in granulosa cells.

SUBMITTER: Oktem O

PROVIDER: S-EPMC3343059 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature

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Preantral follicle growth is regulated by c-Jun-N-terminal kinase (JNK) pathway.

Oktem Ozgur O Buyuk Erkan E Oktay Kutluk K

Reproductive sciences (Thousand Oaks, Calif.) 20101019 3

c-Jun N-terminal kinase (JNK) pathway has been shown to be essential for cell cycle progression and mitosis. We previously showed that this pathway is activated in mitotic granulosa cells of follicles from transitional to antral stages. In this study, we, therefore, aimed to investigate whether this signaling pathway has any effect on in-vitro growth of murine preantral follicles and granulosa cell cycle control. Two structurally different pharmacologic JNK inhibitors, SP600125 and AS601245, wer ...[more]

PMID: 20959642

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Project description:The c-Jun NH2-terminal kinases (JNKs) are an evolutionarily conserved family of serine/threonine protein kinases that play critical roles in the pathological process in species ranging from insects to mammals. However, the function of JNKs in bacteria-induced intestinal inflammation is still poorly understood. In this study, a fish JNK (CiJNK) pathway was identified, and its potential roles in bacterial muramyl dipeptide (MDP)-induced intestinal inflammation were investigated in Ctenopharyngodon idella. The present CiJNK was found to possess a conserved dual phosphorylation motif (TPY) in a serine/threonine protein kinase (S_TKc) domain and to contain several potential immune-related transcription factor binding sites, including nuclear factor kappa B (NF-κB), activating protein 1 (AP-1), and signal transducer and activator of downstream transcription 3 (STAT3), in its 5' flanking regions. Quantitative real-time PCR results revealed that the mRNA levels of the JNK pathway genes in the intestine were significantly upregulated after challenge with a bacterial pathogen (Aeromonas hydrophila) and MDP in a time-dependent manner. Additionally, the JNK pathway was found to be involved in regulating the MDP-induced expression levels of inflammatory cytokines (IL-6, IL-8, and TNF-α) in the intestine of grass carp. Moreover, the nutritional dipeptide carnosine and Ala-Gln could effectively alleviate MDP-induced intestinal inflammation by regulating the intestinal expression of JNK pathway genes and inflammatory cytokines in grass carp. Finally, fluorescence microscopy and dual-reporter assays indicated that CiJNK could associate with CiMKK4 and CiMKK7 involved in the regulation of the AP-1 signaling pathway. Overall, these results provide the first experimental demonstration that the JNK signaling pathway is involved in the intestinal immune response to MDP challenge in C. idella, which may provide new insight into the pathogenesis of inflammatory bowel disease.

Project description:BackgroundThe objectives of this study was to explore the activation of the extracellular-signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathway and osteogenesis-related factors in the subchondral bone of patients with knee osteoarthritis (OA).MethodsTen patients with primary OA who underwent total knee arthroplasty in the Department of Arthritis Surgery of our hospital were enrolled, and subchondral bone tissue samples were obtained during the operation. He staining and saffron staining were used to observe the arrangement of chondrocytes in the patient tissues. The protein expression levels of JNK, p-JNK, ERK, p-ERK, Runx2 and OMD in subchondral bone were detected by Western Blot. Knee osteoarthritis mice were established. He staining was used to observe the arrangement of subchondral bone cells in the knee joint of mice. Cellular mineralized nodules were determined by alizarin red staining.ResultsFirstly, in general and staining, it was observed that the subchondral bone lesions of knee OA participants were obvious. Compared with normal knee joints, the levels of phosphorylation-c-Jun N-terminal kinase (P-JNK) and phosphorylation-extracellular-signal-regulated kinase (P-ERK) in the subchondral bone of knee arthritis participants were significantly increased (P<0.05). The level of osteomodulin (OMD) was significantly reduced (P<0.05). Secondly, compared with normal mice, the levels of JNK, P-JNK, OMD, ERK, and P-ERK in the model group were significantly different (P<0.05). At 2-8 weeks, the JNK and P-JNK levels in the mice model group increased significantly over time (P<0.05), and the OMD level decreased significantly over time (P<0.05). The levels of ERK and P-ERK fluctuated over time. Thirdly, osteoblasts were treated with different concentrations of anisomycin, and stained with alizarin red after continuous culture for 24 and 48 h, respectively. It was found that all the cells were stained with orange-red mineralized nodules. As the concentration of anisomycin was increased, the number of cell mineralization nodules was significantly larger, and the positive rate of chemical nodules increased. Different concentrations of anisomycin were given to interfere with the osteoblasts of mice. When anisomycin was administered at a dose of 25 ng, the OMD level reached the highest level. When the concentration of anisomycin was increased, the osteocalcin (OCN) level also showed an upward trend.ConclusionsThe process by which the JNK signaling pathway regulates OMD may be closely related to the pathological changes of subchondral bone in patients with knee OA, and is involved in the occurrence and development of knee arthritis.

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Preantral follicle growth is regulated by c-Jun-N-terminal kinase (JNK) pathway.

Publications

Preantral follicle growth is regulated by c-Jun-N-terminal kinase (JNK) pathway.

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