Publications by authors named "C Owen Lovejoy"

213 Publications

An introduction to artificial intelligence in sleep medicine.

J Thorac Dis 2021 Oct;13(10):6095-6098

Department of Life Science and Medicine, King's College London, London, UK.

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http://dx.doi.org/10.21037/jtd-21-1569DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8575827PMC
October 2021

Age-related changes in the energy of human mesenchymal stem cells.

J Cell Physiol 2021 Nov 17. Epub 2021 Nov 17.

Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK.

Aging is a physiological process that leads to a higher risk for the most devastating diseases. There are a number of theories of human aging proposed, and many of them are directly or indirectly linked to mitochondria. Here, we used mesenchymal stem cells (MSCs) from young and older donors to study age-related changes in mitochondrial metabolism. We have found that aging in MSCs is associated with a decrease in mitochondrial membrane potential and lower NADH levels in mitochondria. Mitochondrial DNA content is higher in aged MSCs, but the overall mitochondrial mass is decreased due to increased rates of mitophagy. Despite the higher level of ATP in aged cells, a higher rate of ATP consumption renders them more vulnerable to energy deprivation compared to younger cells. Changes in mitochondrial metabolism in aged MSCs activate the overproduction of reactive oxygen species in mitochondria which is compensated by a higher level of the endogenous antioxidant glutathione. Thus, energy metabolism and redox state are the drivers for the aging of MSCs/mesenchymal stromal cells.
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http://dx.doi.org/10.1002/jcp.30638DOI Listing
November 2021

Epigenetic regulation of nuclear lamina-associated heterochromatin by HAT1 and the acetylation of newly synthesized histones.

Nucleic Acids Res 2021 Nov 12. Epub 2021 Nov 12.

Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA.

A central component of the epigenome is the pattern of histone post-translational modifications that play a critical role in the formation of specific chromatin states. Following DNA replication, nascent chromatin is a 1:1 mixture of parental and newly synthesized histones and the transfer of modification patterns from parental histones to new histones is a fundamental step in epigenetic inheritance. Here we report that loss of HAT1, which acetylates lysines 5 and 12 of newly synthesized histone H4 during replication-coupled chromatin assembly, results in the loss of accessibility of large domains of heterochromatin, termed HAT1-dependent Accessibility Domains (HADs). HADs are mega base-scale domains that comprise ∼10% of the mouse genome. HAT1 globally represses H3 K9 me3 levels and HADs correspond to the regions of the genome that display HAT1-dependent increases in H3 K9me3 peak density. HADs display a high degree of overlap with a subset of Lamin-Associated Domains (LADs). HAT1 is required to maintain nuclear structure and integrity. These results indicate that HAT1 and the acetylation of newly synthesized histones may be critical regulators of the epigenetic inheritance of heterochromatin and suggest a new mechanism for the epigenetic regulation of nuclear lamina-heterochromatin interactions.
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http://dx.doi.org/10.1093/nar/gkab1044DOI Listing
November 2021

Upright walking has driven unique vascular specialization of the hominin ilium.

PeerJ 2021 19;9:e12240. Epub 2021 Oct 19.

Division of Biomedical Sciences and Department of Anthropology, Kent State University, Kent, Ohio, United States.

Background: A novel physis in hominins modulates broadening and shortening of the ilium. We report analysis of a vascular canal system whose origin may be associated with this physis and which appears to be also unique to hominins. Its presence is potentially identifiable in the fossil record by its association with a highly enlarged foramen that is consistently present in modern humans and hominin fossils.

Methods: We measured the diameter of this foramen in humans, fossil hominins, and African great apes and corrected for body size.

Results: The mean relative human foramen diameter is significantly greater than those of either or . Moreover, eight of the nine values of the for these differences in ratios are highly significant and support the ordering of magnitudes: < < . The relative foramen diameter of A.L. 288-1 is above the 75th percentile of all other hominoids and at the high end of humans. The foramen is also present in ARA-VP-6/500.

Conclusions: We posit that the presence and significant enlargement of this foramen in fossils can reasonably serve as an indicator that its anterior inferior iliac spine emerged the unique hominin physis. The foramen can therefore serve as an indicator of hominin iliac ontogenetic specialization for bipedality in fossil taxa.
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http://dx.doi.org/10.7717/peerj.12240DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8532992PMC
October 2021

Environmental vulnerability of the global ocean epipelagic plankton community interactome.

Sci Adv 2021 Aug 27;7(35). Epub 2021 Aug 27.

Université de Nantes, CNRS UMR 6004, LS2N, F-44000 Nantes, France.

Marine plankton form complex communities of interacting organisms at the base of the food web, which sustain oceanic biogeochemical cycles and help regulate climate. Although global surveys are starting to reveal ecological drivers underlying planktonic community structure and predicted climate change responses, it is unclear how community-scale species interactions will be affected by climate change. Here, we leveraged Oceans sampling to infer a global ocean cross-domain plankton co-occurrence network-the community interactome-and used niche modeling to assess its vulnerabilities to environmental change. Globally, this revealed a plankton interactome self-organized latitudinally into marine biomes (Trades, Westerlies, Polar) and more connected poleward. Integrated niche modeling revealed biome-specific community interactome responses to environmental change and forecasted the most affected lineages for each community. These results provide baseline approaches to assess community structure and organismal interactions under climate scenarios while identifying plausible plankton bioindicators for ocean monitoring of climate change.
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http://dx.doi.org/10.1126/sciadv.abg1921DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8397264PMC
August 2021
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