Publications by authors named "Chia-Wei Cheng"

24 Publications

  • Page 1 of 1

Reprogramming of H3K9bhb at regulatory elements is a key feature of fasting in the small intestine.

Cell Rep 2021 Nov;37(8):110044

Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. Electronic address:

β-hydroxybutyrate (β-OHB) is an essential metabolic energy source during fasting and functions as a chromatin regulator by lysine β-hydroxybutyrylation (Kbhb) modification of the core histones H3 and H4. We report that Kbhb on histone H3 (H3K9bhb) is enriched at proximal promoters of critical gene subsets associated with lipolytic and ketogenic metabolic pathways in small intestine (SI) crypts during fasting. Similar Kbhb enrichment is observed in Lgr5 stem cell-enriched epithelial spheroids treated with β-OHB in vitro. Combinatorial chromatin state analysis reveals that H3K9bhb is associated with active chromatin states and that fasting enriches for an H3K9bhb-H3K27ac signature at active metabolic gene promoters and distal enhancer elements. Intestinal knockout of Hmgcs2 results in marked loss of H3K9bhb-associated loci, suggesting that local production of β-OHB is responsible for chromatin reprogramming within the SI crypt. We conclude that modulation of H3K9bhb in SI crypts is a key gene regulatory event in response to fasting.
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http://dx.doi.org/10.1016/j.celrep.2021.110044DOI Listing
November 2021

Identifying Cell-Type-Specific Metabolic Signatures Using Transcriptome and Proteome Analyses.

Curr Protoc 2021 Sep;1(9):e245

Columbia Stem Cell Initiative, Department of Genetics and Development, Columbia University Irving Medical Center, New York, New York.

Studies in various tissues have revealed a central role of metabolic pathways in regulating adult stem cell function in tissue regeneration and tumor initiation. The unique metabolic dependences or preferences of adult stem cells, therefore, are emerging as a new category of therapeutic target. Recently, advanced methods including high-resolution metabolomics, proteomics, and transcriptomics have been developed to address the growing interest in stem cell metabolism. A practical framework integrating the omics analyses is needed to systematically perform metabolic characterization in a cell-type-specific manner. Here, we leverage recent advances in transcriptomics and proteomics research to identify cell-type-specific metabolic features by reconstructing cell identity using genes and the encoded enzymes involved in major metabolic pathways. We provide protocols for cell isolation, transcriptome and proteome analyses, and metabolite profiling and measurement. The workflow for mapping cell-type-specific metabolic signatures presented here, although initially developed for intestinal crypt cells, can be easily implemented for cell populations in other tissues, and is highly compatible with most public datasets. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Intestinal crypt isolation and cell population purification Basic Protocol 2: Transcriptome analyses for cell-type-specific metabolic gene expression Basic Protocol 3: Proteome analyses for cell-type-specific metabolic enzyme levels Basic Protocol 4: Metabolite profiling and measurement.
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http://dx.doi.org/10.1002/cpz1.245DOI Listing
September 2021

Crosstalk between Renal and Vascular Calcium Signaling: The Link between Nephrolithiasis and Vascular Calcification.

Int J Mol Sci 2021 Mar 30;22(7). Epub 2021 Mar 30.

Department of Urology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704302, Taiwan.

Calcium (Ca) is an important mediator of multicellular homeostasis and is involved in several diseases. The interplay among the kidney, bone, intestine, and parathyroid gland in Ca homeostasis is strictly modulated by numerous hormones and signaling pathways. The calcium-sensing receptor (CaSR) is a G protein-coupled receptor, that is expressed in calcitropic tissues such as the parathyroid gland and the kidney, plays a pivotal role in Ca regulation. CaSR is important for renal Ca, as a mutation in this receptor leads to hypercalciuria and calcium nephrolithiasis. In addition, CaSR is also widely expressed in the vascular system, including vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) and participates in the process of vascular calcification. Aberrant Ca sensing by the kidney and VSMCs, owing to altered CaSR expression or function, is associated with the formation of nephrolithiasis and vascular calcification. Based on emerging epidemiological evidence, patients with nephrolithiasis have a higher risk of vascular calcification, but the exact mechanism linking the two conditions is unclear. However, a dysregulation in Ca homeostasis and dysfunction in CaSR might be the connection between the two. This review summarizes renal calcium handling and calcium signaling in the vascular system, with a special focus on the link between nephrolithiasis and vascular calcification.
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http://dx.doi.org/10.3390/ijms22073590DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8036726PMC
March 2021

Introductions to the community: Early-career researchers in the time of COVID-19.

Cell Stem Cell 2021 Apr;28(4):600-602

COVID-19 has unfortunately halted lab work, conferences, and in-person networking, which is especially detrimental to researchers just starting their labs. Through social media and our reviewer networks, we met some early-career stem cell investigators impacted by the closures. Here, they introduce themselves and their research to our readers.
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http://dx.doi.org/10.1016/j.stem.2021.03.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8015247PMC
April 2021

100 Years of Exploiting Diet and Nutrition for Tissue Regeneration.

Cell Stem Cell 2021 03;28(3):370-373

Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biology, MIT, Cambridge, MA 02139, USA; Department of Pathology, Massachusetts General Hospital Boston and Harvard Medical School, Boston, MA 02114, USA. Electronic address:

In this forum piece, we review progress in exploiting diet and nutrition for enhancing tissue regeneration with a particular emphasis on how dietary composition and diet-induced physiology influence adult stem cell biology.
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http://dx.doi.org/10.1016/j.stem.2021.02.014DOI Listing
March 2021

Nutritional Control of Intestinal Stem Cells in Homeostasis and Tumorigenesis.

Trends Endocrinol Metab 2021 01 1;32(1):20-35. Epub 2020 Dec 1.

David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA; Department of Biology, MIT, Cambridge, MA, USA; Broad Institute of Harvard and MIT, Cambridge, MA, USA; Departments of Pathology, Gastroenterology, and Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, USA. Electronic address:

Food and nutrition have a profound impact on organismal health and diseases, and tissue-specific adult stem cells play a crucial role in coordinating tissue maintenance by responding to dietary cues. Emerging evidence indicates that adult intestinal stem cells (ISCs) actively adjust their fate decisions in response to diets and nutritional states to drive intestinal adaptation. Here, we review the signaling mechanisms mediating the dietary responses imposed by caloric intake and nutritional composition (i.e., macronutrients and micronutrients), fasting-feeding patterns, diet-induced growth factors, and microbiota on ISCs and their relevance to the beginnings of intestinal tumors.
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http://dx.doi.org/10.1016/j.tem.2020.11.003DOI Listing
January 2021

Strategies for Measuring Induction of Fatty Acid Oxidation in Intestinal Stem and Progenitor Cells.

Methods Mol Biol 2020 ;2171:53-64

Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, USA.

This protocol describes a multipronged approach that we have created to determine the transcriptional induction of fatty acid oxidation (FAO) genes in Lgr5 intestinal stem cells and a subsequent metabolomics-based approach for assessing fatty acid utilization in the mammalian intestinal crypt. More specifically, we describe methods for crypt isolation followed by a FACS-based purification of stem and progenitor populations and RNA-sequencing analysis. Using this workflow, we can determine both basal gene expression profiles of key metabolic genes as well as corresponding changes in response to altered metabolic states, such as fasting. Subsequently, we describe a complementary metabolomics-based approach that we have developed to assess fatty acid uptake and utilization in the crypt using C stable isotope tracing. Combining these approaches, one can gain a better understanding of substrate utilization and the preceding transcriptional changes that accommodate these reactions in physiologic states of low carbohydrate utilization or during overabundance of dietary lipids.
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http://dx.doi.org/10.1007/978-1-0716-0747-3_4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8065345PMC
March 2021

Region-Specific Proteome Changes of the Intestinal Epithelium during Aging and Dietary Restriction.

Cell Rep 2020 04;31(4):107565

Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany. Electronic address:

The small intestine is responsible for nutrient absorption and one of the most important interfaces between the environment and the body. During aging, changes of the epithelium lead to food malabsorption and reduced barrier function, thus increasing disease risk. The drivers of these alterations remain poorly understood. Here, we compare the proteomes of intestinal crypts from mice across different anatomical regions and ages. We find that aging alters epithelial immunity, metabolism, and cell proliferation and is accompanied by region-dependent skewing in the cellular composition of the epithelium. Of note, short-term dietary restriction followed by refeeding partially restores the epithelium by promoting stem cell differentiation toward the secretory lineage. We identify Hmgcs2 (3-hydroxy-3-methylglutaryl-coenzyme A [CoA] synthetase 2), the rate-limiting enzyme for ketogenesis, as a modulator of stem cell differentiation that responds to dietary changes, and we provide an atlas of region- and age-dependent proteome changes of the small intestine.
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http://dx.doi.org/10.1016/j.celrep.2020.107565DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7446723PMC
April 2020

Ketone Body Signaling Mediates Intestinal Stem Cell Homeostasis and Adaptation to Diet.

Cell 2019 08;178(5):1115-1131.e15

Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02139, USA; Department of Biology, MIT, Cambridge, MA 02139, USA; Department of Pathology, Massachusetts General Hospital Boston and Harvard Medical School, Boston, MA 02114, USA; Klarman Cell Observatory, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA. Electronic address:

Little is known about how metabolites couple tissue-specific stem cell function with physiology. Here we show that, in the mammalian small intestine, the expression of Hmgcs2 (3-hydroxy-3-methylglutaryl-CoA synthetase 2), the gene encoding the rate-limiting enzyme in the production of ketone bodies, including beta-hydroxybutyrate (βOHB), distinguishes self-renewing Lgr5 stem cells (ISCs) from differentiated cell types. Hmgcs2 loss depletes βOHB levels in Lgr5 ISCs and skews their differentiation toward secretory cell fates, which can be rescued by exogenous βOHB and class I histone deacetylase (HDAC) inhibitor treatment. Mechanistically, βOHB acts by inhibiting HDACs to reinforce Notch signaling, instructing ISC self-renewal and lineage decisions. Notably, although a high-fat ketogenic diet elevates ISC function and post-injury regeneration through βOHB-mediated Notch signaling, a glucose-supplemented diet has the opposite effects. These findings reveal how control of βOHB-activated signaling in ISCs by diet helps to fine-tune stem cell adaptation in homeostasis and injury.
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http://dx.doi.org/10.1016/j.cell.2019.07.048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6732196PMC
August 2019

Fasting Activates Fatty Acid Oxidation to Enhance Intestinal Stem Cell Function during Homeostasis and Aging.

Cell Stem Cell 2018 05;22(5):769-778.e4

The David H. Koch Institute for Integrative Cancer Research at MIT, Department of Biology, MIT, Cambridge, MA 02139, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA. Electronic address:

Diet has a profound effect on tissue regeneration in diverse organisms, and low caloric states such as intermittent fasting have beneficial effects on organismal health and age-associated loss of tissue function. The role of adult stem and progenitor cells in responding to short-term fasting and whether such responses improve regeneration are not well studied. Here we show that a 24 hr fast augments intestinal stem cell (ISC) function in young and aged mice by inducing a fatty acid oxidation (FAO) program and that pharmacological activation of this program mimics many effects of fasting. Acute genetic disruption of Cpt1a, the rate-limiting enzyme in FAO, abrogates ISC-enhancing effects of fasting, but long-term Cpt1a deletion decreases ISC numbers and function, implicating a role for FAO in ISC maintenance. These findings highlight a role for FAO in mediating pro-regenerative effects of fasting in intestinal biology, and they may represent a viable strategy for enhancing intestinal regeneration.
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http://dx.doi.org/10.1016/j.stem.2018.04.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5940005PMC
May 2018

FAOund the Link: Phospholipid Remodeling and Intestinal Stem Cell Growth and Tumorigenesis.

Cell Stem Cell 2018 02;22(2):141-143

Koch Institute for Integrative Cancer Research at MIT and Department of Biology, MIT, Cambridge, MA 02142, USA; Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA. Electronic address:

In this issue of Cell Stem Cell, Wang et al. (2018) identify a novel link between Lpcat3-mediated phospholipid remodeling (the Lands cycle) and cholesterol biosynthesis that modulates intestinal stem cell proliferation and tumorigenesis. Notably, inhibition of cholesterol biosynthesis dampens many of the Lpcat3-deficiency-mediated effects in the intestine.
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http://dx.doi.org/10.1016/j.stem.2018.01.009DOI Listing
February 2018

Fasting-Mimicking Diet Promotes Ngn3-Driven β-Cell Regeneration to Reverse Diabetes.

Cell 2017 02;168(5):775-788.e12

Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089-0191, USA; Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027, USA; IFOM FIRC Institute of Molecular Oncology, Via Adamello 16, Milan 20139, Italy. Electronic address:

Stem-cell-based therapies can potentially reverse organ dysfunction and diseases, but the removal of impaired tissue and activation of a program leading to organ regeneration pose major challenges. In mice, a 4-day fasting mimicking diet (FMD) induces a stepwise expression of Sox17 and Pdx-1, followed by Ngn3-driven generation of insulin-producing β cells, resembling that observed during pancreatic development. FMD cycles restore insulin secretion and glucose homeostasis in both type 2 and type 1 diabetes mouse models. In human type 1 diabetes pancreatic islets, fasting conditions reduce PKA and mTOR activity and induce Sox2 and Ngn3 expression and insulin production. The effects of the FMD are reversed by IGF-1 treatment and recapitulated by PKA and mTOR inhibition. These results indicate that a FMD promotes the reprogramming of pancreatic cells to restore insulin generation in islets from T1D patients and reverse both T1D and T2D phenotypes in mouse models. PAPERCLIP.
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http://dx.doi.org/10.1016/j.cell.2017.01.040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5357144PMC
February 2017

Fasting-mimicking diet and markers/risk factors for aging, diabetes, cancer, and cardiovascular disease.

Sci Transl Med 2017 02;9(377)

Longevity Institute, School of Gerontology, and Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.

Calorie restriction or changes in dietary composition can enhance healthy aging, but the inability of most subjects to adhere to chronic and extreme diets, as well as potentially adverse effects, limits their application. We randomized 100 generally healthy participants from the United States into two study arms and tested the effects of a fasting-mimicking diet (FMD)-low in calories, sugars, and protein but high in unsaturated fats-on markers/risk factors associated with aging and age-related diseases. We compared subjects who followed 3 months of an unrestricted diet to subjects who consumed the FMD for 5 consecutive days per month for 3 months. Three FMD cycles reduced body weight, trunk, and total body fat; lowered blood pressure; and decreased insulin-like growth factor 1 (IGF-1). No serious adverse effects were reported. After 3 months, control diet subjects were crossed over to the FMD program, resulting in a total of 71 subjects completing three FMD cycles. A post hoc analysis of subjects from both FMD arms showed that body mass index, blood pressure, fasting glucose, IGF-1, triglycerides, total and low-density lipoprotein cholesterol, and C-reactive protein were more beneficially affected in participants at risk for disease than in subjects who were not at risk. Thus, cycles of a 5-day FMD are safe, feasible, and effective in reducing markers/risk factors for aging and age-related diseases. Larger studies in patients with diagnosed diseases or selected on the basis of risk factors are warranted to confirm the effect of the FMD on disease prevention and treatment.
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http://dx.doi.org/10.1126/scitranslmed.aai8700DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6816332PMC
February 2017

Starving leukemia to induce differentiation.

Nat Med 2017 01;23(1):14-15

Koch Institute for Integrative Cancer Research at MIT and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.

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http://dx.doi.org/10.1038/nm.4259DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5300768PMC
January 2017

Fasting-Mimicking Diet Reduces HO-1 to Promote T Cell-Mediated Tumor Cytotoxicity.

Cancer Cell 2016 07;30(1):136-146

Longevity Institute, Leonard Davis School of Gerontology and Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.

Immune-based interventions are promising strategies to achieve long-term cancer-free survival. Fasting was previously shown to differentially sensitize tumors to chemotherapy while protecting normal cells, including hematopoietic stem and immune cells, from its toxic side effects. Here, we show that the combination of chemotherapy and a fasting-mimicking diet (FMD) increases the levels of bone marrow common lymphoid progenitor cells and cytotoxic CD8(+) tumor-infiltrating lymphocytes (TILs), leading to a major delay in breast cancer and melanoma progression. In breast tumors, this effect is partially mediated by the downregulation of the stress-responsive enzyme heme oxygenase-1 (HO-1). These data indicate that FMD cycles combined with chemotherapy can enhance T cell-dependent targeted killing of cancer cells both by stimulating the hematopoietic system and by enhancing CD8(+)-dependent tumor cytotoxicity.
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http://dx.doi.org/10.1016/j.ccell.2016.06.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5388544PMC
July 2016

Safety and feasibility of fasting in combination with platinum-based chemotherapy.

BMC Cancer 2016 06 10;16:360. Epub 2016 Jun 10.

USC Keck School of Medicine, Norris Comprehensive Cancer Center, 1441 Eastlake Ave. #3440, Los Angeles, CA, 90033, USA.

Background: Short-term starvation prior to chemotherapy administration protects mice against toxicity. We undertook dose-escalation of fasting prior to platinum-based chemotherapy to determine safety and feasibility in cancer patients.

Methods: 3 cohorts fasted before chemotherapy for 24, 48 and 72 h (divided as 48 pre-chemo and 24 post-chemo) and recorded all calories consumed. Feasibility was defined as ≥ 3/6 subjects in each cohort consuming ≤ 200 kcal per 24 h during the fast period without excess toxicity. Oxidative stress was evaluated in leukocytes using the COMET assay. Insulin, glucose, ketones, insulin-like growth factor-1 (IGF-1) and IGF binding proteins (IGFBPs) were measured as biomarkers of the fasting state.

Results: The median age of our 20 subjects was 61, and 85 % were women. Feasibility criteria were met. Fasting-related toxicities were limited to ≤ grade 2, most commonly fatigue, headache, and dizziness. The COMET assay indicated reduced DNA damage in leukocytes from subjects who fasted for ≥48 h (p = 0.08). There was a non-significant trend toward less grade 3 or 4 neutropenia in the 48 and 72 h cohorts compared to 24 h cohort (p = 0.17). IGF-1 levels decreased by 30, 33 and 8 % in the 24, 48 and 72 h fasting cohorts respectively after the first fasting period.

Conclusion: Fasting for 72 h around chemotherapy administration is safe and feasible for cancer patients. Biomarkers such as IGF-1 may facilitate assessment of differences in chemotherapy toxicity in subgroups achieving the physiologic fasting state. An onging randomized trial is studying the effect of 72 h of fasting.

Trial Registration: NCT00936364 , registered propectively on July 9, 2009.
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http://dx.doi.org/10.1186/s12885-016-2370-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4901417PMC
June 2016

IGFBP3 and T1D: Systemic Factors in Colonic Stem Cell Function and Diabetic Enteropathy.

Cell Stem Cell 2015 Oct;17(4):379-80

Koch Institute for Integrative Cancer Research at MIT and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA. Electronic address:

Patients with type 1 diabetes (T1D) often experience gastrointestinal enteropathy (DE) of unclear etiology. Now in Cell Stem Cell, D'Addio et al. (2015) utilize organoid culture models to study the roles of stem cells in DE and show that circulating IGF/IGFBP3 controls colonic stem cell function during homeostasis and in T1D patients.
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http://dx.doi.org/10.1016/j.stem.2015.09.008DOI Listing
October 2015

A Periodic Diet that Mimics Fasting Promotes Multi-System Regeneration, Enhanced Cognitive Performance, and Healthspan.

Cell Metab 2015 Jul 18;22(1):86-99. Epub 2015 Jun 18.

Longevity Institute, School of Gerontology, and Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA; IFOM, FIRC Institute of Molecular Oncology, 20139 Milano, Italy. Electronic address:

Prolonged fasting (PF) promotes stress resistance, but its effects on longevity are poorly understood. We show that alternating PF and nutrient-rich medium extended yeast lifespan independently of established pro-longevity genes. In mice, 4 days of a diet that mimics fasting (FMD), developed to minimize the burden of PF, decreased the size of multiple organs/systems, an effect followed upon re-feeding by an elevated number of progenitor and stem cells and regeneration. Bi-monthly FMD cycles started at middle age extended longevity, lowered visceral fat, reduced cancer incidence and skin lesions, rejuvenated the immune system, and retarded bone mineral density loss. In old mice, FMD cycles promoted hippocampal neurogenesis, lowered IGF-1 levels and PKA activity, elevated NeuroD1, and improved cognitive performance. In a pilot clinical trial, three FMD cycles decreased risk factors/biomarkers for aging, diabetes, cardiovascular disease, and cancer without major adverse effects, providing support for the use of FMDs to promote healthspan.
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http://dx.doi.org/10.1016/j.cmet.2015.05.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4509734PMC
July 2015

Identification of trans,trans-2,4-decadienal metabolites in mouse and human cells using liquid chromatography-mass spectrometry.

Chem Res Toxicol 2014 Oct 7;27(10):1707-19. Epub 2014 Oct 7.

National Environmental Health Research Center, National Health Research Institutes , Zhunan 35053, Taiwan.

trans,trans-2,4-Decadienal (tt-DDE), a lipid peroxidation product of linolieic acid, is the most abundant aldehyde identified in cooking oil fumes and is readily detectable in food products as well as in restaurant emissions. Previously, we have reported the toxicological effects of tt-DDE in vitro and in vivo. However, the metabolic pathways of tt-DDE in vivo remain unclear. In our present study, we combined liquid chromatography-mass spectrometry with triple quadrupole and time-of-flight to identify tt-DDE metabolites in the urine of mice orally administered tt-DDE. We identified two tt-DDE metabolites, 2,4-decadienoic acid and cysteine-conjugated 2,4-decadien-1-ol, in the urine of mice gavaged with tt-DDE and in human hepatoma cell cultures. The structure of 2,4-decadienoic acid was confirmed upon comparison of its tandem mass spectrometry (MS/MS) spectrum and retention time with those of synthetic standards. The moieties of cysteine and alcohol on cysteine-conjugated 2,4-decadien-1-ol were validated by treating cell cultures with stable-isotope-labeled cysteine and 4-methylpyrazole, an alcohol dehydrogenase inhibitor. The MS/MS spectra of a cysteine standard and ionized cysteine detached from cysteine-conjugated 2,4-decadien-1-ol were identical. Two metabolic pathways for the biotransformation of tt-DDE in vivo are proposed: (i) the oxidation of tt-DDE to the corresponding carboxylic acid, 2,4-decadienoic acid, in liver cells and (ii) glutathione (GHS) conjugation, GSH breakdown, and aldehyde reduction, which generate cysteine-conjugated 2,4-decadien-1-ol in both liver and lung cells. In conclusion, this platform can be used to identify tt-DDE metabolites, and cysteine-conjugated 2,4-decadien-1-ol can serve as a biomarker for assessing exposure to tt-DDE.
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http://dx.doi.org/10.1021/tx500199bDOI Listing
October 2014

Prolonged fasting reduces IGF-1/PKA to promote hematopoietic-stem-cell-based regeneration and reverse immunosuppression.

Cell Stem Cell 2014 Jun;14(6):810-23

Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, CA 90089, USA; Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at USC, Keck School of Medicine, University of Southern California, 1425 San Pablo Street, Los Angeles, CA 90033, USA; IFOM, FIRC Institute of Molecular Oncology, Via Adamello, 16, 20139 Milano, Italy. Electronic address:

Immune system defects are at the center of aging and a range of diseases. Here, we show that prolonged fasting reduces circulating IGF-1 levels and PKA activity in various cell populations, leading to signal transduction changes in long-term hematopoietic stem cells (LT-HSCs) and niche cells that promote stress resistance, self-renewal, and lineage-balanced regeneration. Multiple cycles of fasting abated the immunosuppression and mortality caused by chemotherapy and reversed age-dependent myeloid-bias in mice, in agreement with preliminary data on the protection of lymphocytes from chemotoxicity in fasting patients. The proregenerative effects of fasting on stem cells were recapitulated by deficiencies in either IGF-1 or PKA and blunted by exogenous IGF-1. These findings link the reduced levels of IGF-1 caused by fasting to PKA signaling and establish their crucial role in regulating hematopoietic stem cell protection, self-renewal, and regeneration.
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http://dx.doi.org/10.1016/j.stem.2014.04.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4102383PMC
June 2014

Low protein intake is associated with a major reduction in IGF-1, cancer, and overall mortality in the 65 and younger but not older population.

Cell Metab 2014 Mar;19(3):407-17

Davis School of Gerontology, University of Southern California, Los Angeles, CA 90033, USA; Longevity Institute, University of Southern California, Los Angeles, CA 90033, USA. Electronic address:

Mice and humans with growth hormone receptor/IGF-1 deficiencies display major reductions in age-related diseases. Because protein restriction reduces GHR-IGF-1 activity, we examined links between protein intake and mortality. Respondents aged 50-65 reporting high protein intake had a 75% increase in overall mortality and a 4-fold increase in cancer death risk during the following 18 years. These associations were either abolished or attenuated if the proteins were plant derived. Conversely, high protein intake was associated with reduced cancer and overall mortality in respondents over 65, but a 5-fold increase in diabetes mortality across all ages. Mouse studies confirmed the effect of high protein intake and GHR-IGF-1 signaling on the incidence and progression of breast and melanoma tumors, but also the detrimental effects of a low protein diet in the very old. These results suggest that low protein intake during middle age followed by moderate to high protein consumption in old adults may optimize healthspan and longevity.
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http://dx.doi.org/10.1016/j.cmet.2014.02.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3988204PMC
March 2014

Growth hormone receptor deficiency is associated with a major reduction in pro-aging signaling, cancer, and diabetes in humans.

Sci Transl Med 2011 Feb;3(70):70ra13

Institute of Endocrinology, Metabolism and Reproduction, Quito, Ecuador.

Mutations in growth signaling pathways extend life span, as well as protect against age-dependent DNA damage in yeast and decrease insulin resistance and cancer in mice. To test their effect in humans, we monitored for 22 years Ecuadorian individuals who carry mutations in the growth hormone receptor (GHR) gene that lead to severe GHR and IGF-1 (insulin-like growth factor-1) deficiencies. We combined this information with surveys to identify the cause and age of death for individuals in this community who died before this period. The individuals with GHR deficiency exhibited only one nonlethal malignancy and no cases of diabetes, in contrast to a prevalence of 17% for cancer and 5% for diabetes in control subjects. A possible explanation for the very low incidence of cancer was suggested by in vitro studies: Serum from subjects with GHR deficiency reduced DNA breaks but increased apoptosis in human mammary epithelial cells treated with hydrogen peroxide. Serum from GHR-deficient subjects also caused reduced expression of RAS, PKA (protein kinase A), and TOR (target of rapamycin) and up-regulation of SOD2 (superoxide dismutase 2) in treated cells, changes that promote cellular protection and life-span extension in model organisms. We also observed reduced insulin concentrations (1.4 μU/ml versus 4.4 μU/ml in unaffected relatives) and a very low HOMA-IR (homeostatic model assessment-insulin resistance) index (0.34 versus 0.96 in unaffected relatives) in individuals with GHR deficiency, indicating higher insulin sensitivity, which could explain the absence of diabetes in these subjects. These results provide evidence for a role of evolutionarily conserved pathways in the control of aging and disease burden in humans.
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http://dx.doi.org/10.1126/scitranslmed.3001845DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3357623PMC
February 2011

A novel DNA selection and direct extraction process and its application in DNA recombination.

Electrophoresis 2011 Feb 30;32(3-4):423-30. Epub 2010 Dec 30.

Institute of Applied Mechanics, National Taiwan University, Taipei, Taiwan.

In the conventional bench-top approach, the DNA recombination process is time- and effort-consuming due to laborious procedures lasting from several hours to a day. A novel DNA selection and direct extraction process has been proposed, integrated and tested on chip. The integrative microfluidic chip can perform the whole procedure of DNA recombination, including DNA digestion, gel electrophoresis, DNA extraction and insert-vector ligation within 1 h. In this high-throughput design, the manual gel cutting was replaced by an automatic processing system that performed high-quality and high-recovery efficiency in DNA extraction process. With no need of gel-dissolving reagents and manipulation, the application of selection and direct extraction process could significantly eliminate the risks from UV and EtBr and also facilitate DNA recombination. Reliable output with high success rate of cloning has been achieved with a significant reduction in operational hazards, required materials, efforts and time.
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http://dx.doi.org/10.1002/elps.201000449DOI Listing
February 2011
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