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105
result(s) for
"Lu, Yi-Chien"
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Single-cell microRNA-mRNA co-sequencing reveals non-genetic heterogeneity and mechanisms of microRNA regulation
2019
Measuring multiple omics profiles from the same single cell opens up the opportunity to decode molecular regulation that underlies intercellular heterogeneity in development and disease. Here, we present co-sequencing of microRNAs and mRNAs in the same single cell using a half-cell genomics approach. This method demonstrates good robustness (~95% success rate) and reproducibility (
R
2
= 0.93 for both microRNAs and mRNAs), yielding paired half-cell microRNA and mRNA profiles, which we can independently validate. By linking the level of microRNAs to the expression of predicted target mRNAs across 19 single cells that are phenotypically identical, we observe that the predicted targets are significantly anti-correlated with the variation of abundantly expressed microRNAs. This suggests that microRNA expression variability alone may lead to non-genetic cell-to-cell heterogeneity. Genome-scale analysis of paired microRNA-mRNA co-profiles further allows us to derive and validate regulatory relationships of cellular pathways controlling microRNA expression and intercellular variability.
Single-cell RNA sequencing allows characterizing cell-to-cell heterogeneity at transcriptome scale. Here, the authors present an approach that enables microRNA and mRNA sequencing in the same single cell, providing insights into the origins of non-genetic cellular variability and mechanisms of miRNA regulation.
Journal Article
Functional Roles of Calreticulin in Cancer Biology
2015
Calreticulin is a highly conserved endoplasmic reticulum chaperone protein which participates in various cellular processes. It was first identified as a Ca2+-binding protein in 1974. Accumulated evidences indicate that calreticulin has great impacts for the development of different cancers and the effect of calreticulin on tumor formation and progression may depend on cell types and clinical stages. Cell surface calreticulin is considered as an “eat-me” signal and promotes phagocytic uptake of cancer cells by immune system. Moreover, several reports reveal that manipulation of calreticulin levels profoundly affects cancer cell proliferation and angiogenesis as well as differentiation. In addition to immunogenicity and tumorigenesis, interactions between calreticulin and integrins have been described during cell adhesion, which is an essential process for cancer metastasis. Integrins are heterodimeric transmembrane receptors which connect extracellular matrix and intracellular cytoskeleton and trigger inside-out or outside-in signaling transduction. More and more evidences reveal that proteins binding to integrins might affect integrin-cytoskeleton interaction and therefore influence ability of cell adhesion. Here, we reviewed the biological roles of calreticulin and summarized the potential mechanisms of calreticulin in regulating mRNA stability and therefore contributed to cancer metastasis.
Journal Article
Correlation between hand grip strength and regional muscle mass in older Asian adults: an observational study
by
Chan, Jessica
,
Kosik, Russell Oliver
,
Yao, Melissa Min-Szu
in
Absorptiometry, Photon
,
Aged
,
Aged, 80 and over
2022
Background
Previous research has demonstrated a correlation between hand grip strength (HGS) and muscle strength. This study aims to determine the relationship between HGS and muscle mass in older Asian adults.
Methods
We retrospectively reviewed the dual-energy X-ray absorptiometry (DXA) records of 907 older adults (239 (26.4%) men and 668 (73.6%) women) at one medical institution in Taipei, Taiwan, from January 2019, to December 2020. Average age was 74.80 ± 9.43 and 72.93 ± 9.09 for the males and females respectively. The inclusion criteria were: 1) aged 60 and older, 2) underwent a full-body DXA scan, and 3) performed hand grip measurements. Patients with duplicate results, incomplete records, stroke history, and other neurological diseases were excluded. Regional skeletal muscle mass was measured using DXA. HGS was measured using a Jamar handheld dynamometer.
Results
Total lean muscle mass (kg) averaged 43.63 ± 5.81 and 33.16 ± 4.32 for the males and females respectively. Average HGS (kg) was 28.81 ± 9.87 and 19.19 ± 6.17 for the males and females respectively. In both sexes, HGS and regional muscle mass consistently declined after 60 years of age. The rates of decline per decade in upper and lower extremity muscle mass and HGS were 7.06, 4.95, and 12.30%, respectively, for the males, and 3.36, 4.44, and 12.48%, respectively, for the females. In men, HGS significantly correlated with upper (
r
= 0.576,
p
< 0.001) and lower extremity muscle mass (
r
= 0.532,
p
< 0.001). In women, the correlations between HGS and upper extremity muscle mass (
r
= 0.262,
p
< 0.001) and lower extremity muscle mass (
r
= 0.364,
p <
0.001) were less strong, though also statistically significant.
Conclusion
Muscle mass and HGS decline with advancing age in both sexes, though the correlation is stronger in men. HGS measurements are an accurate proxy for muscle mass in older Asian adults, particularly in males.
Journal Article
Arginine methylation controls growth regulation by E2F-1
2012
E2F transcription factors are implicated in diverse cellular functions. The founding member, E2F‐1, is endowed with contradictory activities, being able to promote cell‐cycle progression and induce apoptosis. However, the mechanisms that underlie the opposing outcomes of E2F‐1 activation remain largely unknown. We show here that E2F‐1 is directly methylated by PRMT5 (protein arginine methyltransferase 5), and that arginine methylation is responsible for regulating its biochemical and functional properties, which impacts on E2F‐1‐dependent growth control. Thus, depleting PRMT5 causes increased E2F‐1 protein levels, which coincides with decreased growth rate and associated apoptosis. Arginine methylation influences E2F‐1 protein stability, and the enhanced transcription of a variety of downstream target genes reflects increased E2F‐1 DNA‐binding activity. Importantly, E2F‐1 is methylated in tumour cells, and a reduced level of methylation is evident under DNA damage conditions that allow E2F‐1 stabilization and give rise to apoptosis. Significantly, in a subgroup of colorectal cancer, high levels of PRMT5 frequently coincide with low levels of E2F‐1 and reflect a poor clinical outcome. Our results establish that arginine methylation regulates the biological activity of E2F‐1 activity, and raise the possibility that arginine methylation contributes to tumourigenesis by influencing the E2F pathway.
The transcription factor E2F‐1 regulates the cell cycle and apoptosis. E2F‐1 is arginine methylated by PRMT5, leading to degradation and increased cell growth. In colorectal cancer, high levels of PRMT5 correlate with low E2F‐1 and poor clinical outcome.
Journal Article
Tubacin, an HDAC6 Selective Inhibitor, Reduces the Replication of the Japanese Encephalitis Virus via the Decrease of Viral RNA Synthesis
2017
Japanese encephalitis virus (JEV), a neurotropic flavivirus, annually causes over 30,000 Japanese Encephalitis (JE) cases in East and Southeast Asia. Histone deacetylases (HDACs) modulate lysine acetylation of histones and non-histone proteins, regulating many processes including inflammation and antiviral immune response. This study investigated antiviral activity of pan- and selective-HDAC inhibitors as host-targeting agents against JEV. Among HDAC inhibitors, selective HDAC6 inhibitors (tubastatin-A (TBSA) and tubacin) concentration-dependently inhibited JEV-induced cytopathic effect and apoptosis, as well as reduced virus yield in human cerebellar medulloblastoma cells. The 50% inhibitory concentration (IC50) values of virus yield was 0.26 μM for tubacin and 1.75 μM for TBSA, respectively. Tubacin (IC50 of 1.52 μM), but not TBSA, meaningfully blocked the production of intracellular infectious virus particles. In time-of-addition assays, the greatest potency of antiviral activity was observed in the mode of pre-treatment with tubacin (IC50 of 1.89 μM) compared to simultaneous (IC50 of 4.88 μM) and post-treatment (IC50 of 2.05 μM) modes. Interestingly, tubacin induced the hyperacetylation of a HDAC6 substrate Hsp90 and reduced the interaction of Hsp90 with JEV NS5 protein. Novobiocin, an Hsp90 inhibitor, diminished the NS5 protein amount and virus replication in JEV-infected cells. Meantime, tubacin suppressed the NS5 expression and antisense RNA genome synthesis in infected cells. Tubacin-induced Hsp90 hyperacetylation was suggested to influence the NS5 activity in JEV replication. Therefore, tubacin had a high potential of a host-targeting agent against JEV, exhibiting preventive and therapeutic activities against JEV infection.
Journal Article
Dual-energy X-ray absorptiometry-assessed adipose tissues in metabolically unhealthy normal weight Asians
by
Chan, Wing P.
,
Lin, Ying Chin
,
Yen, Amy Ming-Fang
in
692/499
,
692/699/317
,
Absorptiometry, Photon - methods
2019
Normal body mass index (BMI) is associated with lower risk for cardiometabolic diseases. However, there is a subset of individuals with BMI in this range who present with this metabolic abnormality (called metabolically unhealthy normal weight, MUHNW). Here we aimed to assess the adipose characteristics of people with MUHNW using dual-energy X-ray absorptiometry (DXA). This study included 3259 people with normal BMI who underwent health examinations from January 1, 2007 through December 31, 2016. Body fat percentage (%BF), android-gynoid percent fat ratio (AG ratio), and visceral adipose tissue (VAT) were measured simultaneously using DXA CoreScan software. Those with MUHNW comprised 12.67% of the sample. Among those with MUHNW, 71.6% of the women and 56.5% of the men showed high VAT amounts, but less than 40% of either showed high %BFs. Furthermore, considering the combined effects of fat amount and distribution, a normal BMI accompanied by high AG ratio and/or high VAT mass but low %BF presents a much higher risk for metabolic syndrome than when %BF is high, most predominantly in women. In conclusion, using DXA-measured abdominal fat, particularly VAT accumulation, is clinically more important than using %BF when assessing metabolic syndrome in those with normal BMI.
Journal Article
Distance from the Community to the City Center Is a Vital Determinant of Dietary Diversity Score for Rural Community-Dwelling Older Adults in Taiwan
2025
Background: There was little knowledge of the dietary diversity of older adults in rural areas, with limited studies examining their nutritional status and related factors. This study aimed to assess the nutritional status of older adults in rural communities in Taiwan and explore the association between characteristics and the dietary diversity score (DDS). Methods: We collected data on sociodemographic, nutritional status, and DDS. The DDS was estimated based on nutritional intake using a 24 h dietary recall (24HR). Participants were grouped by distance from the city center into three categories (0–4 km, 4–8 km, and >8 km) to assess their correlation with food diversity. Results: A total of 567 participants were included, of whom 81.3% were women, and 65.5% were over 75 years of age. Of the participants, 154 lived within 4 km of the city center, 255 lived 4–8 km away, and 158 resided in remote communities (>8 km from the city center). Out of 538 participants who completed the dietary questionnaire, 274 (50.9%) were categorized as having low dietary diversity (DDS ≤ 4), while 264 (49.1%) were categorized as having high dietary diversity (DDS > 4). Conclusions: Our results showed the distance from the community to the city center significantly influences the DDS of the residents in rural communities. Nearly half of the rural population has a low DDS. The implementation of the research project aimed to determine the feasibility of daily nutrition evaluation and optimization programs for the elderly in rural areas is crucial in the future.
Journal Article
Prevalence of Osteoporosis and Low Bone Mass in Older Chinese Population Based on Bone Mineral Density at Multiple Skeletal Sites
by
Chan, Wing P.
,
Chieng, Poon-Ung
,
Lin, Yen-Kuang
in
692/700/1421/2770
,
692/700/478/174
,
692/700/478/2772
2016
Diagnosis of osteoporosis is based on bone mineral density (BMD) measurement, which is site dependent and commonly discordant between measurement sites. We aimed to determine the prevalence of osteoporosis diagnosed based on BMD T-scores measured by dual-energy x-ray absorptiometry (DXA) at different sites: the lumbar spine (LS) alone, femoral neck (FN) alone, or both. A total of 1712 women and 2028 men with LS and FN BMD measurements were enrolled. Over 50% discordance was found between osteoporosis classifications based on T-scores measured at the LS and FN. Use of the lowest T-scores measured at both the LS and right and left FN (rather than one site) significantly increased the prevalence of osteoporosis from 4.03 to 10.75% in postmenopausal women and 1.82 to 4.29% in men aged ≧50 years (
p
< 0.001). The trends of overall and age-adjusted prevalence of osteoporosis were similar in women and men. Osteoporosis was diagnosed at a higher rate if the USA reference rather than the Asia reference was used to calculate the T-score (26.64% vs. 10.75%). In conclusion, diagnosis based on the lowest T-score from multiple site BMD measurement can increase the prevalence of osteoporosis, demonstrating the higher sensitivity of the multiple site measurement strategy.
Journal Article
Functional evaluation of therapeutic response of HCC827 lung cancer to bevacizumab and erlotinib targeted therapy using dynamic contrast-enhanced and diffusion-weighted MRI
by
Cho, Kuan-Hung
,
Chen, Jyh-Horng
,
Chen, Yi-Fang
in
Adenocarcinoma
,
Angiogenesis
,
Angiogenesis Inhibitors - administration & dosage
2017
This study aimed to investigate the therapeutic responses of lung cancer mice models with adenocarcinoma HCC827 (gefitinib sensitive) and HCC827R (gefitinib resistant) to the epidermal growth factor receptor-tyrosine kinase inhibitor erlotinib alone and in combination with the anti-angiogenesis agent bevacizumab using dynamic contrast enhanced (DCE) and diffusion-weighted MRI. In the HCC827 model, temporal changes in DCE-MRI derived parameters (Ktrans, kep, and iAUC90) and apparent diffusion coefficient (ADC) were significantly correlated with tumor size. Ktrans and iAUC90 significantly decreased at week 2 in the groups receiving erlotinib alone and in combination with bevacizumab, whereas kep decreased at week 1 and 2 in both treatment groups. In addition, there was a significant difference in iAUC90 between the treatment groups at week 1. Compared to the control group of HCC827, there was a significant reduction in microvessel density and increased tumor apoptosis in the two treatment group. ADC value increased in the erlotinib alone group at week 1 and week 2, and in the erlotinib combined with bevacizumab group at week 2. Enlarged areas of central tumor necrosis were associated with a higher ADC value. However, progressive enlargement of the tumors but no significant differences in DCE parameters or ADC were noted in the HCC827R model. These results showed that both erlotinib alone and in combination with bevacizumab could effectively inhibit tumor growth in the gefitinib-sensitive lung cancer mice model, and that this was associated with decreased vascular perfusion, increased ADC percentage, decreased microvessel density, and increased tumor apoptosis with a two-week treatment cycle.
Journal Article
Effects of Paclobutrazol on Reproductive and Vegetative Traits of Phalaenopsis Join Grace ‘TH288-4’
2024
Phalaenopsis is the most popular potted plant worldwide. However, its typically long stalks often lead to increased shipping costs and risks. This study investigates the effectiveness of varying the concentration, timing, and frequency of paclobutrazol (PP333) applications on shortening the stalk of Phalaenopsis Join Grace ‘TH288-4’. Concurrently, it also examines the potential for producing visually appealing and single-flower potted phalaenopsis products by means of truncation. Mature phalaenopsis plants were moved to a cool room in the seventh week to induce flowering. Four experimental groups were established based on different PP333 application schedules: the control (CK) group, with reverse osmosis water application in the second week; the T2 group, with a single application in the second week; the T2T3 group, with applications in both the second and third weeks; and the T7T8 group, with applications in the seventh and eighth weeks. The PP333 concentrations used were 250, 500, 750, and 1000 mg·L−1, applied as foliar sprays. The results showed that the shortest stalks, measured from the base to the first flower, were observed in the T2 group treated with PP333 at 750 mg·L−1 and in the T2T3 group with PP333 at 500, 750, and 1000 mg·L−1. These treatments resulted in stalk lengths of 19.18–22.17 cm, which are 67.2–71.6% shorter than the controls. PP333 application had minimal effect on the stalk diameter, pedicel length, flower width, length, and length/width ratio. However, root diameter was thicker in plants treated with PP333 compared with the control plants. For producing single-flower phalaenopsis, a foliar spray of 750 mg·L−1 PP333 is recommended approximately a month before moving the plants to cooler conditions, followed by truncation, retaining only the first flower. As a result, this study establishes a PP333 treatment protocol for phalaenopsis, offering a strategy to effectively shorten the stalks.
Journal Article