• Molecules and Cells
• /
• 제42권12호
• /
• pp.828-835
• /
• 2019

PIWI Argonaute proteins and Piwi-interacting RNAs (piRNAs) are expressed in all animal species and play a critical role in cellular defense by inhibiting the activation of transposable elements in the germline. Recently, new evidence suggests that PIWI proteins and piRNAs also play important roles in various somatic tissues, including neurons. This review summarizes the neuronal functions of the PIWI-piRNA pathway in multiple animal species, including their involvement in axon regeneration, behavior, memory formation, and transgenerational epigenetic inheritance of adaptive memory. This review also discusses the consequences of dysregulation of neuronal PIWI-piRNA pathways in certain neurological disorders, including neurodevelopmental and neurodegenerative diseases. A full understanding of neuronal PIWI-piRNA pathways will ultimately provide novel insights into small RNA biology and could potentially provide precise targets for therapeutic applications.

• Molecules and Cells
• /
• 제41권8호
• /
• pp.705-716
• /
• 2018

The endoplasmic reticulum (ER) is a critical organelle for protein synthesis, folding and modification, and lipid synthesis and calcium storage. Dysregulation of ER functions leads to the accumulation of misfolded- or unfolded-protein in the ER lumen, and this triggers the unfolded protein response (UPR), which restores ER homeostasis. The UPR is characterized by three distinct downstream signaling pathways that promote cell survival or apoptosis depending on the stressor, the intensity and duration of ER stress, and the cell type. Mammalian cells express the UPR transducers IRE1, PERK, and ATF6, which control transcriptional and translational responses to ER stress. Direct links between ER stress and immune responses are also evident, but the mechanisms by which UPR signaling cascades are coordinated with immunity remain unclear. This review discusses recent investigations of the roles of ER stress in immune responses that lead to differentiation, maturation, and cytokine expression in immune cells. Further understanding of how ER stress contributes to the pathogenesis of immune disorders will facilitate the development of novel therapies that target UPR pathways.

• BMB Reports
• /
• 제52권1호
• /
• pp.35-41
• /
• 2019

Cellular senescence, a permanent state of cell cycle arrest, is believed to have originally evolved to limit the proliferation of old or damaged cells. However, it has been recently shown that cellular senescence is a physiological and pathological program contributing to embryogenesis, immune response, and wound repair, as well as aging and age-related diseases. Unlike replicative senescence associated with telomere attrition, premature senescence rapidly occurs in response to various intrinsic and extrinsic insults. Thus, cellular senescence has also been considered suppressive mechanism of tumorigenesis. Current studies have revealed that therapy-induced senescence (TIS), a type of senescence caused by traditional cancer therapy, could play a critical role in cancer treatment. In this review, we outline the key features and the molecular pathways of cellular senescence. Better understanding of cellular senescence will provide insights into the development of powerful strategies to control cellular senescence for therapeutic benefit. Lastly, we discuss existing strategies for the induction of cancer cell senescence to improve efficacy of anticancer therapy.

• 대한화학회지
• /
• 제40권6호
• /
• pp.401-408
• /
• 1996

일반적으로 고온 초전도체들은 2차원적인 구조를 가지고 있으며, 2차원적인 구조가 초전도 물성과 어떠한 관계를 갖는가를 이해하는 것은 매우 중요하다. 본 논문에서는 초전도체 속의 전자기체를 기체분자운동론을 사용하여 각 차원에서의 상태 방정식을 유도하였으며, 그 기체가 액화될 때의 온도, 임계온도를 구하였다. 그 결과 전자의 자유도를 제한시킴에 따라 임계온도가 상승함을 알 수 있었다. 이것은 2차원적인 구조물질에 1차원적인 전자유통 경로가 있을 경우 여러가지의 임계온도를 가질 수 있음을 의미한다.

• 한국의료질향상학회지
• /
• 제9권1호
• /
• pp.34-51
• /
• 2002

Background : The purpose for this study is to develop a critical pathway of bullectomy for spontaneous pneumothorax patients. Methods : For this study a conceptual framework of critical pathway was developed through a review of the literature including five critical pathways which are currently being used in USA, and opinions of the critical pathway development team members at Y university hospital. In order to identify the service contents required by these patients and to draw up a preliminary critical pathway, 33 cases of medical records of patients who had received bullectomy for spontaneous pneumothorax between September, 2000 to August, 2001 at the Respiratory Center of Y university hospital in Seoul was analyzed. Results : In order to test the clinical validity of the preliminary critical pathway, it was applied to ten patients who had received bullectomy for spontaneous pneumothorax from October, 2001 to December, 2001. The average discharge day was 4.89th post operation day, six patients discharged on the fourth post operation day which was the expected day, one patients discharged one day earlier than the expected day, one patient discharged three days later than the expected day, and one patient discharged six days later than the expected day. There were variances between the critical pathway and the actual practice. The variances came from tests, medications, and treatments. One item that showed variance in clinical applications was complemented, and three items were decided not to be corrected for the final determination of the critical pathway. Conclusion : This critical pathway is applicable to the care of patients with bullectomy for spontaneous pneumothorax, but it needs more clinical applications to grasp varied variances.

• The Korean Journal of Physiology and Pharmacology
• /
• 제18권2호
• /
• pp.109-120
• /
• 2014

The epothilones are a class of microtubule inhibitors that exhibit a strong antitumor activity. UTD2 is a novel epothilone analog generated by genetic manipulation of the polyketide biosynthetic gene cluster. This study investigated the effects of UTD2 on the actin cytoskeleton and its critical regulators, and the signaling pathways which are essential for cell motility, growth and survival in MCF-7 breast cancer cells. Results showed that UTD2 inhibited the cellular functions of actin cytoskeleton, such as wound-closure, migration and invasion, as well as adhesion. Our study further demonstrated that UTD2 suppressed Rac1 GTPase activation and reduced the activity of PAK1, which is a downstream effector of Rac1, while the activity of Cdc42 was not affected. Additionally, the phosphorylation of p38 and ERK were significantly inhibited, but the phosphorylation of JNK remained the same after UTD2 treatment. Moreover, UTD2 inhibited the activity and mRNA expression of MMP-2, which plays a key role in cell motility. UTD2 also reduced the phosphorylation of Akt, which is an important signaling kinase regulating the cell survival through Rac1. Furthermore, UTD2 interrupted the synergy between Rac1 and Raf in focus formation assays. Taken together, these results indicated that UTD2 exerted multiple effects on the actin cytoskeleton and signaling pathways associated with Rac1. This study provided novel insights into the molecular mechanism of the antineoplastic and antimetastatic activities of epothilones. Our findings also suggest that the signaling pathways regulated by Rac1 may be evaluated as biomarkers for the response to therapy in clinical trials of epothilones.

• Tuberculosis and Respiratory Diseases
• /
• 제54권4호
• /
• pp.403-414
• /
• 2003

연구배경 : Proteasome 억제가 세포의 apoptosis에 미치는 영향은 세포 종류에 따라 차이를 보이고 있다. 그러나 아직까지 폐암 세포에서 proteasome 억제가 미치는 효과 및 그 기전에 관해서는 확실하게 규명되어 있지 못한 상태이다. 본 연구에서는 폐암 세포주에서 proteasome 억제에 의한 apoptosis의 유도 유무를 관찰하고, 그 기전을 규명하고자 하였다. 방 법 : 폐암 세포주인 A549와 NCI-H157 세포에 proteasome 억제제인 MG132와 PS-341을 투여하고 세포의 생존율을 MTT 분석으로 평가하였고, apoptosis 유무를 PARP 단백에 대한 Western 분석으로 확인하였다. Proteasome 억제가 caspase 3와 JNK의 활성화에 미치는 효과를 각각 Western 분석과 immunocomplex kinase 분석으로 평가하였다. Proteasome 억제제를 투여하고 항 apoptosis 경로인 ERK와 cIAP1에 미치는 효과를 Western 분석으로 평가하였다. 결 과 : A549와 NCI-H157 세포에 MG132를 투여하였을 때, 세포생존율의 감소가 관찰되었고, 이는 apoptosis의 유도에 의한 것으로 확인되었다. MG132와 PS-341 처치로 caspase 3와 JNK가 활성화되었다. 반면에 활성화된 ERK의 발현과 cIAP1의 발현은 감소하였다. 결 론 : 폐암 세포에서 proteasome 억제에 의한 apoptosis에는 caspase 3, JNK와 같은 apoptosis 유도 경로의 활성화와 함께 항 apoptosis 경로의 억제가 관여할 것으로 생각된다.

• BMB Reports
• /
• 제37권1호
• /
• pp.53-58
• /
• 2004

With advances in determining the entire DNA sequence of the human genome, it is now critical to systematically identify the function of a number of genes in the human genome. These biological challenges, especially those in human diseases, should be addressed in human cells in which conventional (e.g. genetic) approaches have been extremely difficult to implement. To overcome this, several approaches have been initiated. This review will focus on the development of a novel 'chemical genetic/genomic approach' that uses small molecules to 'probe and identify' the function of genes in specific biological processes or pathways in human cells. Due to the close relationship of small molecules with drugs, these systematic and integrative studies will lead to the 'medicinal systems biology approach' which is critical to 'formulate and modulate' complex biological (disease) networks by small molecules (drugs) in human bio-systems.

• BMB Reports
• /
• 제51권10호
• /
• pp.493-499
• /
• 2018

Cellular senescence is a state of permanent cell-cycle arrest triggered by different internal and external stimuli. This phenomenon is considered to be both beneficial and detrimental depending on the cell types and biological contexts. During normal embryonic development and after tissue injury, cellular senescence is critical for tissue remodeling. In addition, this process is useful for arresting growth of tumor cells, particularly during early onset of tumorigenesis. However, accumulation of senescent cells decreases tissue regenerative capabilities and induces inflammation, which is responsible for cancer and organismal aging. Therefore cellular senescence has to be tightly regulated, and dysregulation might lead to the aging and human diseases. Among many regulators of cellular senescence, in this review, I will focus on microRNAs, small non-coding RNAs playing critical roles in diverse biological events including cellular senescence.

• Molecules and Cells
• /
• 제43권9호
• /
• pp.774-783
• /
• 2020

The lung has a vital function in gas exchange between the blood and the external atmosphere. It also has a critical role in the immune defense against external pathogens and environmental factors. While the lung is classified as a relatively quiescent organ with little homeostatic turnover, it shows robust regenerative capacity in response to injury, mediated by the resident stem/progenitor cells. During regeneration, regionally distinct epithelial cell populations with specific functions are generated from several different types of stem/progenitor cells localized within four histologically distinguished regions: trachea, bronchi, bronchioles, and alveoli. WNT signaling is one of the key signaling pathways involved in regulating many types of stem/progenitor cells in various organs. In addition to its developmental role in the embryonic and fetal lung, WNT signaling is critical for lung homeostasis and regeneration. In this minireview, we summarize and discuss recent advances in the understanding of the role of WNT signaling in lung regeneration with an emphasis on stem/progenitor cells.