Honors & Awards
Postdoctoral Research Abroad Program Scholarship, Ministry of Science and Technology, Taiwan (2021)
The Award of Academic Research Thesis in Doctor, National Taiwan University (2020)
Award of Veterinary Elite, Doctor of Philosophy Scholarship Award, Dr. Robert Chong-Dao Lee Foundation (2019)
Postdoctoral Fellowship, Higher Education Sprout Project, Ministry of Education, Taiwan (2019)
The Award of Academic Research Thesis in Doctor, National Taiwan University (2019)
Mr. G. X. Liu Outstanding Research Award, National Taiwan University (2018)
Graduate Students Study Abroad Program Scholarship, Ministry of Science and Technology, Taiwan (2018)
The Award of Academic Research Thesis in Doctor, National Taiwan University (2017)
2016 – 2017 Novus International Graduate Scholarship, Novus International, Inc. (2017)
Mr. Y. S. Yu scholarship, the Agricultural Association of Taiwan (2016)
Honorable Mention, National biotechnology innovative entrepreneurship competition, Ministry of Education, Taiwan (2016)
The Award of Academic Research Thesis in Doctor, National Taiwan University (2016)
The Award of Academic Research Thesis in Master, National Taiwan University (2015)
Young Scientist Oral Presentation Award of the Chinese Society of Animal Science, Chinese Society of Animal Science (2012)
Doctor of Philosophy, National Taiwan University (2019)
Master of Science, National Taiwan University (2013)
Bachelor of Science, National Chiayi University (2011)
Bereketeab Haileselassie, Postdoctoral Faculty Sponsor
Long-term dietary restriction ameliorates ageing-related renal fibrosis in male mice by normalizing mitochondrial functions and autophagy.
As the kidneys age, gradual changes in the structures and functions of mitochondria occur. Dietary restriction (DR) can play a protective role in ageing-associated renal decline, however the exact mechanisms involved are still unclear. This study aims to clarify the beneficial effects of long-term DR on renal ageing and to explore the potential mechanisms of mitochondrial homeostasis. Eight-week-old C57BL/6 male mice (n=30) were randomly divided into three groups, Young-AL (AL, ad libitum), Aged-AL, and Aged-DR (60% intake of AL). Mice were sacrificed at age of 7months (Young) or 22months (Aged). Heavier body and kidney weights were associated with ageing, but DR reduced these increases in aged mice. Ageing caused extensive tubulointerstitial fibrosis and glomerulosclerosis in the kidney. Giant mitochondria with looser and irregular crista were observed in Aged-AL kidneys. DR retarded these morphological alterations in aged kidneys. In addition, DR reversed the increase of MDA caused by ageing. Renal ATP level was elevated by DR treatment. Mitochondrial-related proteins were analysed to elucidate this association. Ageing downregulated the renal levels of VDAC, FOXO1, SOD2, LC3I and II, and upregulated the renal levels of MFN2 and PINK1. In contrast, DR elevated the levels of VDAC, FOXO1, and LC3I and reduced the ratio of LC3II to LC3I in aged kidneys. To conclude, impaired mitochondria, increased oxidative stress, and severe fibrosis were noticed in the aged kidneys, and DR improved these changes by increasing functional mitochondria and promoting autophagic clearance.
View details for DOI 10.1007/s10522-022-09993-8
View details for PubMedID 36183304
ALDH2 Expression, Alcohol Intake, and Semen Parameters Among East Asian Men.
The Journal of urology
Inactivating mutations in mitochondrial aldehyde dehydrogenase-2 (ALDH2) are highly prevalent. The most common variant allele, ALDH2*2, is present in 40-50% of East Asians, and causes acetaldehyde accumulation, flushing, and tachycardia after alcohol intake. The relationship between alcohol intake and ALDH2 genotype on semen parameters remains unknown.We conducted a cross-sectional study to determine the association between ALDH2 genotype, alcohol consumption, and semen parameters among East Asian men. Volunteers completed a survey and submitted a semen sample for analysis. Participants were genotyped to determine ALDH2 status (ALDH2*1/*1, ALDH2*1/*2, ALDH2*2/*2) and immunohistochemical staining was used to determine protein expression of ALDH2 in spermatozoa.45 (40.2%) of 112 men were ALDH2*2 carriers. Among ALDH2*2 carriers, alcohol consumption was associated with significantly lower total sperm motility (median 20% [interquartile range 11-42%] vs 43% [IQR 31-57%], p=0.005) and progressive sperm motility (19% [IQR 11-37%] vs 36% [IQR 25-53%], p=0.008). Among alcohol consumers, ALDH2*2 carriers had significantly lower total sperm motility (20% [IQR 11-42%] vs 41% [IQR 19-57%], p=0.02), progressive sperm motility (19% [IQR 11-37%] vs 37% [IQR 17-50%], p=0.02) and total motile sperm count (28M [IQR 9-79M] vs 71M [IQR 23-150M], p=0.05) compared to ALDH2*1/*1 individuals. Secondly, ALDH2 expression in human spermatozoa was significantly lower in ALDH2*2 carriers (ALDH2*1/*1 vs ALDH2*1/*2, p=0.01; ALDH2*1/*1 vs ALDH2*2/*2, p<0.001).Our findings suggest genotyping ALDH2, coupled with alcohol cessation counseling, may improve semen parameters among men.
View details for DOI 10.1097/JU.0000000000002682
View details for PubMedID 35344413
Early-onset dietary restriction maintains mitochondrial health, autophagy and ER function in the left ventricle during aging.
The Journal of nutritional biochemistry
Dietary restriction (DR) exerts healthy benefits, including heart functions. However, the cardioprotective role of DR is till controversial among researchers due to the variation of DR conditions. The present study focuses on the protective effect of early-onset DR on cardiac injury using mitochondrial structure and expression of protein associated with mitochondrial homeostasis, autophagy and endoplasmic reticulum (ER) function as measures.METHODS: Two-month-old mice were fed with a breeding diet ad libitum (AL) or DR (60% of AL) for 3 (Young) or 20 (Aged) months.RESULTS: Body weight increased with aging, whereas DR treatment kept body weight consistent. DR mice exhibited a higher relative heart weight than AL mice. DR mice displayed lower plasma glucose levels, compared with AL groups. Furthermore, Aged-AL, but not Aged-DR mice, had increased collagen content and morphological distortions in the left ventricle (LV). Aged-DR mice had a higher ATP and lower TBARS in the LV than Aged-AL mice. Mitochondrial morphology was detected by electron microscopy; Aged-AL mice had increased abnormal morphology of mitochondria. Treatment with DR reduced abnormal mitochondrial accumulation. Aging elevated the protein expressions of mitochondrial functions and ER-induced apoptosis. Aging downregulated autophagy-related proteins and chaperones in the heart. Dietary restriction reversed those protein expressions.CONCLUSIONS: The present study demonstrated a beneficial effect of early onset DR on cardiac aging. The age-dependent mitochondrial dysfunction and protein quality control dysregulation was significantly reversed by long-term DR, demonstrating a concordance with the beneficial effect in the heart.
View details for DOI 10.1016/j.jnutbio.2022.108944
View details for PubMedID 35017002
Determination of mitochondrial functions and damage in kidney in female LeeSung minipigs with a high-fat diet-induced obesity
ARCHIVES OF PHYSIOLOGY AND BIOCHEMISTRY
The purpose of this study was to investigate the nexus between mitochondrial function and kidney injury by using a dietary-induced obese minipig model. Female Lee-Sung minipigs feeding a high-fat diet (HFD) for 6 months exhibited obesity, hyperglycaemia and dyslipidemia. HFD elevated the levels of plasma biomarkers related to renal injury, including symmetric dimethylarginine, creatinine and urea nitrogen. An extensive structural change in tubules and glomeruli was observed in HFD-fed pigs. A great amount of triacylglycerol was accumulated in HFD kidney compared to control kidney, whereas a reduction of ATP level and antioxidant capacity were exhibited in HFD kidney. Moreover, HFD altered the expressions of mitochondrial-related protein in renal cortex. To conclude, long-term HFD feeding to Lee-Sung minipigs induced obesity and kidney injury accompanied by abnormal mitochondrial functions in the renal cortex, suggesting an interrelationship with renal disease progression.
View details for DOI 10.1080/13813455.2021.1949022
View details for Web of Science ID 000680276800001
View details for PubMedID 34338085
Novel and prevalent non-East Asian ALDH2 variants; Implications for global susceptibility to aldehydes' toxicity.
2020; 55: 102753
BACKGROUND: Aldehyde dehydrogenase 2 (ALDH2) catalyzes the detoxification of aliphatic aldehydes, including acetaldehyde. About 45% of Han Chinese (East Asians), accounting for 8% of humans, carry a single point mutation in ALDH2*2 (E504K) that leads to accumulation of toxic reactive aldehydes.METHODS: Sequencing of a small Mexican cohort and a search in the ExAC genomic database for additional ALDH2 variants common in various ethnic groups was set to identify missense variants. These were evaluated in vitro, and in cultured cells expressing these new and common variants.FINDINGS: In a cohort of Hispanic donors, we identified 2 novel mutations in ALDH2. Using the ExAC genomic database, we found these identified variants and at least three other ALDH2 variants with a single point mutation among Latino, African, South Asian, and Finnish ethnic groups, at a frequency of >5/1000. Although located in different parts of the ALDH2 molecule, these common ALDH2 mutants exhibited a significant reduction in activity compared with the wild type enzyme in vitro and in 3T3 cells overexpressing each of the variants, and a greater ethanol-induced toxicity. As Alda-1, previously identified activator, did not activate some of the new mutant ALDH2 enzymes, we continued the screen and identified Alda-64, which is effective in correcting the loss of activity in most of these new and common ALDH2 variants.INTERPRETATION: Since ~80% of the world population consumes ethanol and since acetaldehyde accumulation contributes to a variety of diseases, the identification of additional inactivating variants of ALDH2 in different ethnic groups may help develop new 'precision medicine' for carriers of these inactive ALDH2.
View details for DOI 10.1016/j.ebiom.2020.102753
View details for PubMedID 32403082
The impact of DRP1 on myocardial fibrosis in the obese minipig
EUROPEAN JOURNAL OF CLINICAL INVESTIGATION
2020; 50 (3): e13204
The heart is a highly oxidative tissue, thus mitochondria play a major role in maintaining optimal cardiac function. Our previous study established a dietary-induced obese minipig with cardiac fibrosis. The aim of this study was to elucidate the role of mitochondrial dynamics in cardiac fibrosis of obese minipigs.Four-month-old Lee-Sung minipigs were randomly divided into two groups: a control group (C) and an obese group (O) by feeding a control diet or a high-fat diet (HFD) for 6 months. Exposure of H9c2 cardiomyoblasts to palmitate was used to explore the effects of high-fat on induction of myocardial injury in vitro.The O pigs displayed greater heart weight and cardiac collagen accumulation. Obese pigs exhibited a lower antioxidant capacity, ATP concentration, and higher oxidative stress in the left ventricle (LV). The HFD caused downregulation in protein expression of PGC-1α and OPA1, and upregulation of DRP1, FIS1, and PINK1 in the LV of O compared to C pigs. Furthermore, palmitate induced apoptosis and decreased ATP content in H9c2 cells. Palmitate elevated the protein expression of DRP1 and PINK1 in these cells. Inhibition of DRP1 protein expression by siDRP1 in H9c2 cells resulted in enhanced ATP and decreased palmitate-induced apoptosis.These results suggest that mitochondrial dynamics were linked to the progression of obesity-related cardiac injury. Inhibition of DRP1 after palmitate exposure in H9c2 cells resulted in improved ATP level and decreased apoptosis in vitro suggesting that mitochondrial fission serves a key role in progression of obesity-induced cardiac fibrosis.
View details for DOI 10.1111/eci.13204
View details for Web of Science ID 000512826100001
View details for PubMedID 31990365
Involvement of pericardial adipose tissue in cardiac fibrosis of dietary-induced obese minipigs-Role of mitochondrial function
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR AND CELL BIOLOGY OF LIPIDS
2019; 1864 (7): 957-965
Heart is a high energy demand organ and cardiac fat is the main local energy source for heart. Alteration in cardiac fat may affect cardiac energy and contribute to heart dysfunction. We previously observed a link between alteration in pericardial fat (PAT) and local adverse effects on myocardial fibrosis in obese minipigs. This study investigated the role of PAT on cardiac energy and mitochondrial function, and elucidated a potential mechanism for PAT in cardiac fibrosis.Five-month-old Lee-Sung minipigs were made obese by feeding a high-fat diet (HFD) for 6 months. The conditioned medium from PAT of obese minipigs (PAT-CM) was collected and H9C2 cells were treated with it to study mechanisms.HFD caused a cardiac energy deficit and fibrosis in the left ventricle. An elevated content of IL6 and malondialdehyde was found in the PAT of obese pigs. Obese pigs exhibited an increased level of oleic acid and a reduced level of saturated fatty acids in PAT compared to control pigs. HFD did not alter the metabolic characteristics of epicardial fat. PAT-CM caused apoptosis of H9C2 cells and inhibited basal mitochondrial respiration and ATP production. Protein expressions for mitochondrial dynamics- (Mfn2, Opa1, Drp1, and Fis1) and a mitophagy-related protein (Parkin) were suppressed by PAT-CM. PAT-CM enhanced the protein expression of LC3II, and the ratio of LC3II/LC3I. To conclude, PAT was involved in cardiac fibrosis of HFD-fed minipigs. The secretomes of PAT impaired mitochondrial functions and caused cardiomyocyte apoptosis in a paracrine manner.
View details for DOI 10.1016/j.bbalip.2019.03.004
View details for Web of Science ID 000467664400001
View details for PubMedID 30872120
The role of pericardial adipose tissue in the heart of obese minipigs
EUROPEAN JOURNAL OF CLINICAL INVESTIGATION
2018; 48 (7): e12942
Pericardial adipose tissue (PAT) volume is highly associated with the presence and severity of cardiometabolic diseases, but the underlying mechanism is unknown. We previously demonstrated that a high-fat diet (HFD) induced metabolic dysregulation, cardiac fibrosis and accumulation of more PAT in minipigs. This study used our obese minipig model to investigate the characteristics of PAT and omental visceral fat (VAT) induced by a HFD, and the potential link between PAT and HFD-related myocardial fibrosis.Five-month-old Lee-Sung minipigs were made obese by feeding a HFD for 6 months.The HFD induced dyslipidemia, cardiac fibrosis and more fat accumulation in the visceral and pericardial depots. The HFD changes the fatty acid composition in the adipose tissue by decreasing the portion of linoleic acid in the VAT and PAT. No arachidonic acid was detected in the VAT and PAT of control pigs, whereas it existed in the same tissues of obese pigs fed the HFD. Compared with the control pigs, elevated levels of malondialdehyde and TNFα were exhibited in the plasma and PAT of obese pigs. HFD induced greater size of adipocytes in VAT and PAT. Higher levels of GH, leptin, OPG, PDGF, resistin, SAA and TGFβ were observed in obese pig PAT compared to VAT.This study demonstrated the similarities and dissimilarities between PAT and VAT under HFD stimulus. In addition, this study suggested that alteration in PAT contributed to the myocardial damage.
View details for DOI 10.1111/eci.12942
View details for Web of Science ID 000436800200003
View details for PubMedID 29682734
Eicosapentaenoic acid protects cardiomyoblasts from lipotoxicity in an autophagy-dependent manner
CELL BIOLOGY AND TOXICOLOGY
2018; 34 (3): 177-189
The cardiovascular health benefits of eicosapentaenoic acid (EPA) have been demonstrated previously; however, the exact mechanism underlying them remains unclear. Our previous study found that lipotoxicity induced cardiomyocyte apoptosis via the inhibition of autophagy. Accordingly, in this study, we investigated whether EPA attenuated lipotoxicity-induced cardiomyocyte apoptosis through autophagy regulation. The role of EPA in mitochondrial dynamics was analyzed as well.To explore how EPA protected against lipotoxicity-induced myocardial injury, cardiomyoblast (H9C2) cells were left untreated or were treated with 400 μM palmitic acid (PAM) and/or 80 μM EPA for 24 h.Excessive PAM treatment induced apoptosis. EPA reduced this PAM-induced apoptosis; however, EPA was unable to ameliorate the effects of PAM when autophagy was blocked by 3-methyladenine and bafilomycin A1. PAM blocked the autophagic flux, thus causing the accumulation of autophagosomes and acid vacuoles, whereas EPA restored the autophagic flux. PAM caused a decrease in polyunsaturated fatty acid (PUFA) content and an increase in saturated fatty acid content in the mitochondrial membrane, while EPA was incorporated in the mitochondrial membrane and caused a significant increase in the PUFA content. PAM also decreased the mitochondrial membrane potential, whereas EPA enhanced it. Finally, PAM elevated the expressions of autophagy-related proteins (LC3I, LC3II, p62) and mitochondrial fission protein (Drp1), whereas EPA inhibited their elevation under PAM treatment.EPA reduces lipotoxicity-induced cardiomyoblast apoptosis through its effects on autophagy.
View details for DOI 10.1007/s10565-017-9406-9
View details for Web of Science ID 000431184800003
View details for PubMedID 28741157
The high-fat diet induces myocardial fibrosis in the metabolically healthy obese minipigs-The role of ER stress and oxidative stress
2017; 36 (3): 760-767
The cellular mechanisms of obesity-induced cardiomyopathy are multiple and not completely elucidated. The objective of this study was to differentiate two obesity-associated cardiomyopathy miniature pig models: one with the metabolic syndrome (MetS), and one with a metabolically healthy obesity (MHO). The cellular responses during the development of obesity-induced cardiomyopathy were investigated.Five-month-old Lee-Sung (MetS) and Lanyu (MHO) minipigs were made obese by feeding a high-fat diet (HFD) for 6 months.Obese pigs exhibited a greater heart weight than control pigs. Interstitial and perivascular fibrosis developed in the myocardium of obese pigs. The HFD induced cardiac lipid accumulation and oxidative stress and also decreased the antioxidant defense in MetS pigs. This diet activated oxidative stress without changing cardiac antioxidant defense and lipid content in MHO pigs. The HFD upregulated the expression of Grp94, CHOP, caspase 12, p62, and LC3II, and increased the ratio of LC3II to LC3I in the left ventricle (LV) of MetS pigs. Compared to obese MetS pigs, less Grp94 and elevated CHOP expression was found in the obese MHO heart. The HFD did not change the ratio of LC3II to LC3I and p62 expression in obese MHO pigs. The obese MetS pigs had an extensive and greater inflammatory response in the plasma than the obese MHO pigs, which had a lesser and milder inflammation.Oxidative stress and ER stress were involved in the progression of MHO-related cardiomyopathy. Inflammation, autophagy, ER stress, oxidative stress, and lipotoxicity participated in the pathological mechanism of MetS-related cardiomyopathy.
View details for DOI 10.1016/j.clnu.2016.06.002
View details for Web of Science ID 000401208700015
View details for PubMedID 27342749
Time-dependent cellular response in the liver and heart in a dietary-induced obese mouse model: the potential role of ER stress and autophagy
EUROPEAN JOURNAL OF NUTRITION
2016; 55 (6): 2031-2043
Both endoplasmic reticulum stress (ER stress) and autophagy are essential for the response of the protein quality control system to cellular stresses. This study investigated the influence of the duration of a high-fat diet (HFD) in mice on tissue-specific cellular responses, specifically with regard to the role of autophagy and ER stress.Male mice aged 6-7 weeks were fed ad libitum with a standard chow diet or with a HFD for 2, 4, 8, or 16 weeks.The HFD progressively increased mean body weight and induced tissue hypertrophy. The expression of PERK was suppressed in the liver after 16 weeks of the HFD and in the heart after 8 weeks of the HFD. Procaspase 12 and its activated form were induced in the liver with the HFD after 2 weeks, but not in the heart over the 16-week period. The activation of hepatic AMPK was elevated following 4 weeks of the HFD, but was inhibited after 16 weeks of the HFD. The ratio of LC3II to LC3I in the liver did not increase except in those mice fed the HFD for 16 weeks. The expression of AMPK and LC3 in the heart did not change over the entire 16 weeks of feeding the HFD. Cleaved PARP was increased in the liver and heart of mice receiving the HFD for 8 weeks.This study provides evidence that a HFD affects the cellular protein quality control processes responsible for metabolic disorder in a tissue- and duration-dependent manner.
View details for DOI 10.1007/s00394-015-1017-8
View details for Web of Science ID 000382751000005
View details for PubMedID 26264388
A nutritional nonalcoholic steatohepatitis minipig model
JOURNAL OF NUTRITIONAL BIOCHEMISTRY
2016; 28: 51-60
The objective of this study was to elucidate whether a Western diet was associated with nonalcoholic steatohepatitis (NASH), and the relationship between NASH, autophagy and endoplasmic reticulum (ER) stress.Four-month-old Lee-Sung minipigs were randomly assigned to two groups: control diet (C) and Western diet (W), for a 5-month experimental period.Feeding a Western diet produced a body composition with more fat, less lean and a greater liver weight. Compared with C pigs, W pigs also exhibited an elevated level of plasma insulin and free fatty acid. The W pigs displayed glucose intolerance, lower circulation antioxidant capacity and greater hepatic oxidative stress. Furthermore, pig fed the W diets had increased collagen accumulation in the liver and elevated systemic inflammation [tumor necrosis factor α and interleukin (IL)-6]. Compared with C pigs, W pigs had higher hepatic ER stress-related protein expression of GRP94, CHOP and caspase-12. The W pigs also had greater hepatic autophagy-related protein expression of p62 and LC3II. In an obesity antibody array analysis, W pigs had higher type 2 diabetes mellitus- (insulin-like growth factor 1, osteoprotegerin and resistin), atherosclerosis- (vascular endothelial growth factor, platelet-derived growth factor-AA and plasminogen activator inhibitor-I) and inflammation- [IL-1, macrophage-stimulating protein alpha, X-linked ectodermal dysplasia receptor and serum amyloid A (SAA)] related protein expressions. In addition, W pigs had greater plasma SAA concentration than C pigs and plasma SAA level was highly associated with IL-6.We successfully established a NASH pig model, and our findings suggested an association of NASH with ER stress and autophagy. The SAA has potential as a novel plasma biomarker for nonalcoholic fatty liver disease pigs.
View details for DOI 10.1016/j.jnutbio.2015.09.029
View details for Web of Science ID 000371359100006
View details for PubMedID 26878782
Development of a dietary-induced metabolic syndrome model using miniature pigs involvement of AMPK and SIRT1
EUROPEAN JOURNAL OF CLINICAL INVESTIGATION
2015; 45 (1): 70-80
During the progression of the metabolic syndrome (MetS), cardiovascular diseases (CVD) appear clinically in many individuals and cause death. As a result, it is essential to set up an optimal animal model to study the mechanism of MetS leading to CVD. SIRT1 and AMPK are the master regulators of lipid and carbohydrate metabolism. The objective of this study was to establish a miniature pig model of Western diet-induced MetS and investigate the role of SIRT1/AMPK during MetS development.Five-month-old Lee-Sung (LS) and Lanyu (LY) minipigs were each randomly assigned to two groups: control diet (C) and Western diet (W), in a 6-month experimental period.Western diet caused obesity in both minipig models. Compared with the CLS pigs, WLS pigs exhibited hypercholesterolaemia. However, WLY pigs maintained a similar plasma lipid profile to the CLY pigs. Western diet caused a lower antioxidant capacity in the liver of both pig models. WLS pigs had higher triglyceride accumulation in the liver than CLS pigs, whereas WLY and CLY pigs had similar hepatic triglyceride accumulation. Compared with CLS pigs, WLS pigs had a lower hepatic SIRT1 expression, whereas WLY pigs had a higher expression of AMPK, FOXO1 and SIRT1 than CLY pigs.Long-term feeding of the Western diet to Lee-Sung miniature pigs not only caused obesity but also induced MetS and fatty liver, whereas Western diet induced obesity in Lanyu pigs without metabolic dysfunctions. SIRT1/AMPK and their downstream pathways might be one of the possible regulators for pathological obesity in Lee-Sung pigs.
View details for DOI 10.1111/eci.12370
View details for Web of Science ID 000347056700009
View details for PubMedID 25376184