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Reconstitution of UCP1 using CRISPR/Cas9 in the white adipose tissue of pigs decreases fat deposition and improves thermogenic capacity

  1. Jianguo Zhaoa,b,2
  1. aState Key Laboratory of Stem Cell and Reproductive Biology, Chinese Academy of Sciences, Chaoyang District, Beijing, China 100101;
  2. bSavaid Medical School, University of Chinese Academy of Sciences, Beijing, China 100049;
  3. cKey Laboratory of Animal Ecology and Conservation Biology, Chinese Academy of Sciences, Chaoyang District, Beijing, China 100101;
  4. dCollege of Life Science, University of Chinese Academy of Sciences, Beijing, China 100049;
  5. eInstitute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China 100101;
  6. fEnergetics Research Group, Zoology Department, University of Aberdeen, Aberdeen AB24 2TZ, United Kingdom;
  7. gDepartment of Animal Science, Yanbian University, Yanji, Jilin, China 133002;
  8. hInstitute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China 100193
  1. Edited by R. Michael Roberts, University of Missouri-Columbia, Columbia, MO, and approved September 14, 2017 (received for review May 12, 2017)

Significance

Uncoupling protein 1 (UCP1) is responsible for brown adipose tissue-mediated thermogenesis and plays a critical role in protecting against cold and regulating energy homeostasis. Modern pigs lack functional UCP1, which makes them susceptible to cold and prone to fat deposition and results in neonatal mortality and decreased production efficiency. In the current study, a CRISPR/Cas9-mediated homologous recombination-independent approach was established, and mouse adiponectin-UCP1 was efficiently inserted into the porcine endogenous UCP1 locus. The resultant UCP1 KI pigs showed an improved ability to maintain body temperature, decreased fat deposition, and increased carcass lean percentage. UCP1 KI pigs are a potentially valuable resource for the pig industry that can improve pig welfare and reduce economic losses.

Abstract

Uncoupling protein 1 (UCP1) is localized on the inner mitochondrial membrane and generates heat by uncoupling ATP synthesis from proton transit across the inner membrane. UCP1 is a key element of nonshivering thermogenesis and is most likely important in the regulation of body adiposity. Pigs (Artiodactyl family Suidae) lack a functional UCP1 gene, resulting in poor thermoregulation and susceptibility to cold, which is an economic and pig welfare issue owing to neonatal mortality. Pigs also have a tendency toward fat accumulation, which may be linked to their lack of UCP1, and thus influences the efficiency of pig production. Here, we report application of a CRISPR/Cas9-mediated, homologous recombination (HR)-independent approach to efficiently insert mouse adiponectin-UCP1 into the porcine endogenous UCP1 locus. The resultant UCP1 knock-in (KI) pigs showed an improved ability to maintain body temperature during acute cold exposure, but they did not have alterations in physical activity levels or total daily energy expenditure (DEE). Furthermore, ectopic UCP1 expression in white adipose tissue (WAT) dramatically decreased fat deposition by 4.89% (P < 0.01), consequently increasing carcass lean percentage (CLP; P < 0.05). Mechanism studies indicated that the loss of fat upon UCP1 activation in WAT was linked to elevated lipolysis. UCP1 KI pigs are a potentially valuable resource for agricultural production through their combination of cold adaptation, which improves pig welfare and reduces economic losses, with reduced fat deposition and increased lean meat production.

Footnotes

  • ?1Q. Zheng, J.L., and J.H. contributed equally to this work.

  • ?2To whom correspondence may be addressed. Email: wangyanfang{at}caas.cn, jinw{at}ioz.ac.cn, or zhaojg{at}ioz.ac.cn.
  • Author contributions: Q. Zhou, Y.W., W.J., and J.Z. designed research; Q. Zheng, J.L., J.H., H.Z., R.Z., X.Z., C.H., G.Q., J.Y., R.S., Q.J., X.W., Y.L., N.Z., Z.P., R.Y., J.R.S., and H.W. performed research; Q. Zheng, J.L., X.Z., C.C., J.R.S., H.W., Q. Zhou, Y.W., and J.Z. analyzed data; and Q. Zheng, J.R.S., Y.W., and J.Z. wrote the paper.

  • Conflict of interest statement: J.Z., Q. Zheng, J.H., G.Q. and W.J. have a pending patent application “Production of transgenic pigs tolerant to cold stimulation with lean phenotype.”

  • This article is a PNAS Direct Submission.

  • This article contains supporting information online at www.danielhellerman.com/lookup/suppl/doi:10.1073/pnas.1707853114/-/DCSupplemental.

Published under the PNAS license.

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