The epidermis regenerates continually to maintain a protective barrier at the body's surface composed of differentiating keratinocytes. Maturation of this stratified tissue requires that keratinocytes undergo wholesale organelle degradation upon reaching the outermost tissue layers to form compacted, anucleate cells. Through live imaging of organotypic cultures of human epidermis, we find that regulated breakdown of mitochondria is critical for epidermal development. Keratinocytes in the upper layers initiate mitochondrial fragmentation, depolarization, and acidification upon upregulating the mitochondrion-tethered autophagy receptor NIX. Depleting NIX compromises epidermal maturation and impairs mitochondrial elimination, whereas ectopic NIX expression accelerates keratinocyte differentiation and induces premature mitochondrial fragmentation via the guanosine triphosphatase (GTPase) DRP1. We further demonstrate that inhibiting DRP1 blocks NIX-mediated mitochondrial breakdown and disrupts epidermal development. Our findings establish mitochondrial degradation as a key step in terminal keratinocyte differentiation and define a pathway operating via the mitophagy receptor NIX in concert with DRP1 to drive epidermal morphogenesis.
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http://dx.doi.org/10.1016/j.celrep.2021.108689 | DOI Listing |
Cell Commun Signal
January 2025
Institute of Animal Reproduction and Food Research, Olsztyn, Poland.
Cryopreservation of bull sperm, crucial for breeding and assisted reproduction, often reduces sperm quality due to oxidative stress. This study examines how oxidative stress during cryopreservation affects peroxiredoxin 5 (PRDX5) and peroxiredoxin 6 (PRDX6) proteins, leading to their translocation and oligomerization in bull sperm. Increased reactive oxygen species (ROS) and nitric oxide (NO) levels were linked to reduced mitochondrial potential, higher DNA fragmentation, and increased membrane fluidity, prompting PRDX5 to move intracellularly and PRDX6 to the cell membrane.
View Article and Find Full Text PDFJ Neurosci
January 2025
Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213;
Huntington's disease (HD), a neurodegenerative disease, affects approximately 30,000 people in the United States, with 200,000 more at risk. Mitochondrial dysfunction caused by mutant huntingtin (mHTT) drives early HD pathophysiology. mHTT binds the translocase of mitochondrial inner membrane (TIM23) complex, inhibiting mitochondrial protein import and altering the mitochondrial proteome.
View Article and Find Full Text PDFJ Cell Sci
January 2025
Zellbiologie, Universität Bayreuth, 95440 Bayreuth, Germany.
Budding yeast cells multiply by asymmetric cell division. During this process, the cell organelles are transported by myosin motors along the actin cytoskeleton into the growing bud, while at the same time some organelles must be retained in the mother cell. The ordered partitioning of organelles depends on highly regulated binding of motor proteins to cargo membranes.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, Missouri, United States of America.
Human neutrophils are abundant, short-lived leukocytes that turn over at a rate of approximately 1011 cells/day via a constitutive apoptosis program. Certain growth factors, inflammatory mediators and infectious agents can delay apoptosis or induce neutrophils to die by other mechanisms. Nonetheless, a large body of data demonstrates that apoptosis of untreated neutrophils typically ensues within 24 hours of cell isolation and in vitro culture.
View Article and Find Full Text PDFJ Physiol Investig
January 2025
Department of Emergency, Shijiazhuang Traditional Chinese Medicine Hospital, Shijiazhuang, China.
Sepsis is a life-threatening condition that often results in severe brain injury, primarily due to excessive inflammation and mitochondrial dysfunction. This study aims to investigate the neuroprotective effects of Apelin-13, a bioactive peptide, in a rat model of sepsis-induced brain injury (SBI). Specifically, we examined the role of Apelin-13 in regulating mitophagy through the phosphatase and tensin homolog-induced putative kinase 1 (PINK1)/Parkin pathway and its impact on nucleotide-binding oligomerization domain-like receptor pyrin domain-containing 3 (NLRP3) inflammasome-mediated pyroptosis and oxidative stress.
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