PMID- 38206362 OWN - NLM STAT- MEDLINE DCOM- 20240206 LR - 20240214 IS - 1432-0428 (Electronic) IS - 0012-186X (Linking) VI - 67 IP - 3 DP - 2024 Mar TI - NRF2 is required for neonatal mouse beta cell growth by maintaining redox balance and promoting mitochondrial biogenesis and function. PG - 547-560 LID - 10.1007/s00125-023-06071-7 [doi] AB - AIMS/HYPOTHESIS: All forms of diabetes result from insufficient functional beta cell mass. Due to the relatively limited expression of several antioxidant enzymes, beta cells are highly vulnerable to pathological levels of reactive oxygen species (ROS), which can lead to the reduction of functional beta cell mass. During early postnatal ages, both human and rodent beta cells go through a burst of proliferation that quickly declines with age. The exact mechanisms that account for neonatal beta cell proliferation are understudied but mitochondrial release of moderated ROS levels has been suggested as one of the main drivers. We previously showed that, apart from its conventional role in protecting beta cells from oxidative stress, the nuclear factor erythroid 2-related factor 2 (NRF2) is also essential for beta cell proliferation. We therefore hypothesised that NRF2, which is activated by ROS, plays an essential role in beta cell proliferation at early postnatal ages. METHODS: Beta cell NRF2 levels and beta cell proliferation were measured in pancreatic sections from non-diabetic human cadaveric donors at different postnatal ages, childhood and adulthood. Pancreatic sections from 1-, 7-, 14- and 28-day-old beta cell-specific Nrf2 (also known as Nfe2l2)-knockout mice (betaNrf2KO) or control (Nrf2(lox/lox)) mice were assessed for beta cell NRF2 levels, beta cell proliferation, beta cell oxidative stress, beta cell death, nuclear beta cell pancreatic duodenal homeobox protein 1 (PDX1) levels and beta cell mass. Seven-day-old betaNrf2KO and Nrf2(lox/lox) mice were injected daily with N-acetylcysteine (NAC) or saline (154 mmol/l NaCl) to explore the potential contribution of oxidative stress to the phenotypes seen in betaNrf2KO mice at early postnatal ages. RNA-seq was performed on 7-day-old betaNrf2KO and Nrf2(lox/lox) mice to investigate the mechanisms by which NRF2 stimulates beta cell proliferation at early postnatal ages. Mitochondrial biogenesis and function were determined using dispersed islets from 7-day-old betaNrf2KO and Nrf2(lox/lox) mice by measuring MitoTracker intensity, mtDNA/gDNA ratio and ATP/ADP ratio. To study the effect of neonatal beta cell-specific Nrf2 deletion on glucose homeostasis in adulthood, blood glucose, plasma insulin and insulin secretion were determined and a GTT was performed on 3-month-old betaNrf2KO and Nrf2(lox/lox) mice fed on regular diet (RD) or high-fat diet (HFD). RESULTS: The expression of the master antioxidant regulator NRF2 was increased at early postnatal ages in both human (1 day to 19 months old, 31%) and mouse (7 days old, 57%) beta cells, and gradually declined with age (8% in adult humans, 3.77% in adult mice). A significant correlation (R(2)=0.568; p=0.001) was found between beta cell proliferation and NRF2 levels in human beta cells. Seven-day-old betaNrf2KO mice showed reduced beta cell proliferation (by 65%), beta cell nuclear PDX1 levels (by 23%) and beta cell mass (by 67%), and increased beta cell oxidative stress (threefold) and beta cell death compared with Nrf2(lox/lox) control mice. NAC injections increased beta cell proliferation in 7-day-old betaNrf2KO mice (3.4-fold) compared with saline-injected betaNrf2KO mice. Interestingly, RNA-seq of islets isolated from 7-day-old betaNrf2KO mice revealed reduced expression of mitochondrial RNA genes and genes involved in the electron transport chain. Islets isolated from 7-day old betaNrf2KO mice presented reduced MitoTracker intensity (by 47%), mtDNA/gDNA ratio (by 75%) and ATP/ADP ratio (by 68%) compared with islets from Nrf2(lox/lox) littermates. Lastly, HFD-fed 3-month-old betaNrf2KO male mice displayed a significant reduction in beta cell mass (by 35%), a mild increase in non-fasting blood glucose (1.2-fold), decreased plasma insulin (by 14%), and reduced glucose tolerance (1.3-fold) compared with HFD-fed Nrf2(lox/lox) mice. CONCLUSIONS/INTERPRETATION: Our study highlights NRF2 as an essential transcription factor for maintaining neonatal redox balance, mitochondrial biogenesis and function and beta cell growth, and for preserving functional beta cell mass in adulthood under metabolic stress. DATA AVAILABILITY: Sequencing data are available in the NCBI Gene Expression Omnibus, accession number GSE242718 ( https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE242718 ). CI - (c) 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. FAU - Baumel-Alterzon, Sharon AU - Baumel-Alterzon S AD - Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA. sharon.alterzon@mssm.edu. AD - Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA. sharon.alterzon@mssm.edu. FAU - Katz, Liora S AU - Katz LS AD - Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA. FAU - Lambertini, Luca AU - Lambertini L AD - Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA. FAU - Tse, Isabelle AU - Tse I AD - Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA. FAU - Heidery, Fatema AU - Heidery F AD - Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA. FAU - Garcia-Ocana, Adolfo AU - Garcia-Ocana A AD - Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes & Metabolism Research Institute at City of Hope, Duarte, CA, USA. FAU - Scott, Donald K AU - Scott DK AD - Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA. AD - Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA. LA - eng GR - DK128387-01A1/DK/NIDDK NIH HHS/United States GR - R01DK114338/DK/NIDDK NIH HHS/United States GR - R01DK130300/DK/NIDDK NIH HHS/United States GR - DK128387-01A1/DK/NIDDK NIH HHS/United States GR - R01DK114338/DK/NIDDK NIH HHS/United States GR - R01DK130300/DK/NIDDK NIH HHS/United States PT - Journal Article DEP - 20240111 PL - Germany TA - Diabetologia JT - Diabetologia JID - 0006777 RN - 0 (Blood Glucose) RN - 0 (Antioxidants) RN - 0 (Reactive Oxygen Species) RN - 0 (NF-E2-Related Factor 2) RN - IY9XDZ35W2 (Glucose) RN - 0 (DNA, Mitochondrial) RN - 8L70Q75FXE (Adenosine Triphosphate) RN - 0 (Insulins) SB - IM MH - Male MH - Humans MH - Mice MH - Animals MH - Child MH - Infant, Newborn MH - Infant MH - Blood Glucose/metabolism MH - Antioxidants/metabolism MH - Reactive Oxygen Species/metabolism MH - NF-E2-Related Factor 2/genetics MH - Animals, Newborn MH - Organelle Biogenesis MH - *Insulin-Secreting Cells/metabolism MH - Glucose/metabolism MH - Oxidation-Reduction MH - DNA, Mitochondrial/metabolism MH - Adenosine Triphosphate/metabolism MH - *Insulins OTO - NOTNLM OT - Beta cell death OT - Beta cell proliferation OT - Diabetes OT - Mitochondria OT - NRF2 OT - Neonatal development OT - Oxidative stress OT - Redox balance EDAT- 2024/01/11 12:42 MHDA- 2024/02/06 06:42 CRDT- 2024/01/11 11:05 PHST- 2023/07/25 00:00 [received] PHST- 2023/11/13 00:00 [accepted] PHST- 2024/02/06 06:42 [medline] PHST- 2024/01/11 12:42 [pubmed] PHST- 2024/01/11 11:05 [entrez] AID - 10.1007/s00125-023-06071-7 [pii] AID - 10.1007/s00125-023-06071-7 [doi] PST - ppublish SO - Diabetologia. 2024 Mar;67(3):547-560. doi: 10.1007/s00125-023-06071-7. Epub 2024 Jan 11.