AK2 is an AMP-sensing negative regulator of BRAF in tumorigenesis.

The RAS-BRAF signaling is a major pathway of cell proliferation and their mutations are frequently found in human cancers. Adenylate kinase 2 (AK2), which modulates balance of adenine nucleotide pool, has been implicated in cell death and cell proliferation independently of its enzyme activity. Recently, the role of AK2 in tumorigenesis was in part elucidated in some cancer types including lung adenocarcinoma and breast cancer, but the underlying mechanism is not clear. Here, we show that AK2 is a BRAF-suppressor. In in vitro assays and cell model, AK2 interacted with BRAF and inhibited BRAF activity and downstream ERK phosphorylation. Energy-deprived conditions in cell model and the addition of AMP to cell lysates strengthened the AK2-BRAF interaction, suggesting that AK2 is involved in the regulation of BRAF activity in response to cell metabolic state. AMP facilitated the AK2-BRAF complex formation through binding to AK2. In a panel of HCC cell lines, AK2 expression was inversely correlated with ERK/MAPK activation, and AK2-knockdown or -knockout increased BRAF activity and promoted cell proliferation. Tumors from HCC patients showed low-AK2 protein expression and increased ERK activation compared to non-tumor tissues and the downregulation of AK2 was also verified by two microarray datasets (TCGA-LIHC and GSE14520). Moreover, AK2/BRAF interaction was abrogated by RAS activation in in vitro assay and cell model and in a mouse model of HRASG12V-driven HCC, and AK2 ablation promoted tumor growth and BRAF activity. AK2 also bound to BRAF inhibitor-insensitive BRAF mutants and attenuated their activities. These findings indicate that AK2 monitoring cellular AMP levels is indeed a negative regulator of BRAF, linking the metabolic status to tumor growth.

Casein kinase-1γ1 and 3 stimulate tumor necrosis factor-induced necroptosis through RIPK3.

Upon necroptosis activation, receptor interacting serine/threonine kinase (RIPK)1 and RIPK3 form a necrosome complex with pseudokinase mixed lineage kinase-like (MLKL). Although protein phosphorylation is a key event for RIPK1 and RIPK3 activation in response to a necroptosis signal, relatively little is known about other factors that might regulate the activity of these kinases or necrosome formation. Through a gain-of-function screen with 546 kinases and 127 phosphatases, we identified casein kinase 1 gamma (CK1γ) as a candidate necroptosis-promoting factor. Here, we show that the decreased activity or amounts of CK1γ1 and CK1γ3, either by treatment with a chemical inhibitor or knockdown in cells, reduced TNFα-induced necroptosis. Conversely, ectopic expression of CK1γ1 or CK1γ3 exacerbated necroptosis, but not apoptosis. Similar to RIPK1 and RIPK3, CK1γ1 was also cleaved at Asp343 by caspase-8 during apoptosis. CK1γ1 and CK1γ3 formed a protein complex and were recruited to the necrosome harboring RIPK1, RIPK3 and MLKL. In particular, an autophosphorylated form of CK1γ3 at Ser344/345 was detected in the necrosome and was required to mediate the necroptosis. In addition, in vitro assays with purified proteins showed that CK1γ phosphorylated RIPK3, affecting its activity, and in vivo assays showed that the CK1γ-specific inhibitor Gi prevented abrupt death in mice with hypothermia in a model of TNFα-induced systemic inflammatory response syndrome. Collectively, these data suggest that CK1γ1 and CK1γ3 are required for TNFα-induced necroptosis likely by regulating RIPK3.

Implementation of the relay server for the ubiquitous integrated biotelemetry system for emergency care (UIBSEC) based on 3.5G HSDPA technology.

When an emergent case occurs, to give proper and immediate emergency treatment to a patient is as important as to transfer him or her to the hospital as early as possible. For this circumstance where first aid usually happens in an ambulance, we developed the Ubiquitous Integrated Biotelemetry System for Emergency Care (UIBSEC) based on wireless 3.5G HSDPA module in order to provide more proper and active medical care to a patient. For this system we performed experimental tests on the HSDPA module to measure practical performance values with respect to throughput and RTT (round-trip-time) and compared the result with the theoretical specifications. In the course of developing this system we created the C#-based Network Solution Library (NSL) which helps drastically reducing the overhead. We applied this library to components of the UIBSEC - two kinds of clients and one central server - and confirmed that it works smoothly in wireless networks and it is useful in the future development process of network applications.

Preliminary study of motion artifact rejection for NIBP measurement in an ambulance.

Motion artifact resulting from patient's movement is a significant source for disturbing accurate noninvasive blood pressure (NIBP) measurement. In an ambulance, patients are exposed to unstable circumstances due to vehicle's movement and vibration during emergency transportation. Since NIBP is indirectly measured using oscillometry based on the change of cuff pressure, it can be affected by motion artifact much more than other biosignals. In this paper, we developed a new NIBP system with improved accuracy by measuring acceleration of the system caused by patient's motion. The NIBP module including a 3-axis accelerometer was directly mounted on a cuff to minimize the interference induced through connecting tube. The results show that the proposed NIBP system has the capability to reject the interference of motion artifact effectively in an ambulance.

HSDPA (3.5G)-based ubiquitous integrated biotelemetry system for emergency care.

We have developed the second prototype system of Ubiquitous Integrated Biotelemetry System for Emergency Care(UIBSEC) using a HSDPA(High Speed Downlink Packet Access) modem to be used by emergency rescuers to get directions from medical doctors in providing emergency medical services for patients in ambulance. Five vital bio-signal instrumentation modules have been implemented, which include noninvasive arterial blood pressure (NIBP), arterial oxygen saturation (SaO2), 6-channel electro-cardiogram(ECG), blood glucose level, and body temperature and real-time motion picture of the patient and GPS information are also taken. Measured patient data, captured motion picture and GPS information are then transferred to a doctor's PC through the HSDPA and TCP/IP networks using stand-alone HSDPA modem. Most prominent feature of the developed system is that it is based on the HSDPA backbone networks available in Korea now, through which we will be able to establish a ubiquitous emergency healthcare service system.

Preliminary evaluation of the use of a CDMA-based emergency telemedicine system.

We have conducted a preliminary evaluation of the use of a code division multiple access (CDMA)-based emergency telemedicine system to be used by emergency rescuers providing first-aid treatment for patients. The prototype system included five instrumentation modules for measuring non-invasive arterial blood pressure (NIBP), arterial oxygen saturation (SpO(2)), six-channel electrocardiogram (ECG), blood glucose concentration and body temperature. The patient data were transferred to a doctor's PC through CDMA and TCP/IP networks using an embedded personal digital assistant (PDA) phone. Performance tests in the laboratory showed that the system provided reliable values with error ranges within +/-1% for heart rate, +/-5 mmHg for NIBP, +/-2% for SpO(2) and +/-1% for glucose. The feasibility of the prototype system was then evaluated with 15 real emergency patients on Jeju Island over a two-month period. Measured data were transmitted from a moving ambulance to the emergency medical centre without significant CDMA connection loss or transmission errors. The average transfer time was 8 min. Four emergency doctors and 11 rescuers completed a questionnaire. There were favourable reviews from the users.

IT-based diagnostic instrumentation systems for personalized healthcare services.

This paper describes recent research and development activities on the diagnostic instruments for personalized healthcare services in Seoul National University. Utilizing the state-of-the-art information technologies (IT), various diagnostic medical instruments have been integrated into a personal wearable device and a home telehealthcare system. We developed a wrist-worn integrated health monitoring device (WIHMD) which performs the measurements of non-invasive blood pressure (NIBP), pulse oximetry (SpO2), electrocardiogram (ECG), respiration rate, heart rate, and body surface temperature and the detection of falls to determine the onset of emergency situation. The WIHMD also analyzes the acquired bio-signals and transmits the resultant data to a healthcare service center through a commercial cellular phone. Two different kinds of IT-based blood glucometer have been developed using a cellular phone and PDA(personal digital assistant) as a main unit. A blood glucometer was also integrated within a wrist pressure measurement module which is interfaced with a cellular phone via Telecommunications Technology Association (TTA) standard in order to provide users with easiness in measuring and handling two important health parameters. Non-intrusive bio-signal measurement systems were developed for the ease of home use. One can measure his ECG on a bed while he is sleeping; measure his ECG, body temperature, bodyfat ratio and weight on a toilet seat; measure his ECG on a chair; and estimate the degree of activity by motion analysis using a camera. Another integrated diagnostic system for home telehealthcare services has been developed to include a 12 channels ECG, a pressure meter for NIBP, a blood glucometer, a bodyfat meter and a spirometer. It is an expert system to analyze the measured health data and based on the diagnostic result, the system provides an appropriate medical consultation. The measured data can be either stored on the system or transmitted to the central server through the internet. We have installed the developed systems on a model house for the performance evaluation and confirmed the possibility of the system as an effective tool for the personalized healthcare services.

An Wearable Energy Expenditure Analysis System based on the 15-channel Whole-body Segment Acceleration Measurement.

The measurement of the amount of energy utilized during physical activity has generated considerable interests from various groups ranging from exercise physiologists to nutritionists and fitness center workers. To date, however, the existing energy expenditure estimation methods are not so reliable and compact. In this paper, we propose a new method for accurately and easily estimating energy expenditure during physical activity with a novel algorithm. This method involves acquiring acceleration signals through a 15-channel whole-body segment acceleration measurement system and then estimating the calories expended using a newly developed algorithm. The results of 3 subjects' experiments were compared with a commercially available mask type indirect calorimeter and a 9-axis accelerometry-based calorimeter. The results demonstrate that the proposed method provides a new and reliable way to estimate human energy expenditure during physical activity.