Mitocytosis, a migrasome-mediated mitochondrial quality-control process.

Damaged mitochondria need to be cleared to maintain the quality of the mitochondrial pool. Here, we report mitocytosis, a migrasome-mediated mitochondrial quality-control process. We found that, upon exposure to mild mitochondrial stresses, damaged mitochondria are transported into migrasomes and subsequently disposed of from migrating cells. Mechanistically, mitocytosis requires positioning of damaged mitochondria at the cell periphery, which occurs because damaged mitochondria avoid binding to inward motor proteins. Functionally, mitocytosis plays an important role in maintaining mitochondrial quality. Enhanced mitocytosis protects cells from mitochondrial stressor-induced loss of mitochondrial membrane potential (MMP) and mitochondrial respiration; conversely, blocking mitocytosis causes loss of MMP and mitochondrial respiration under normal conditions. Physiologically, we demonstrate that mitocytosis is required for maintaining MMP and viability in neutrophils in vivo. We propose that mitocytosis is an important mitochondrial quality-control process in migrating cells, which couples mitochondrial homeostasis with cell migration.

ROS-induced autophagy regulates porcine trophectoderm cell apoptosis, proliferation, and differentiation.

Significant embryo loss remains a serious problem in pig production. Reactive oxygen species (ROS) play a critical role in embryonic implantation and placentation. However, the potential mechanism of ROS on porcine trophectoderm (pTr) cell fate during the peri-implantation period has not been investigated. This study aimed to elucidate the effects of ROS on pTr cell phenotypes and the regulatory role in cell attachment and differentiation. Herein, results showed that exogenous H2O2 inhibited pTr cell viability, arrested the cell cycle at S and G2/M phases, and increased cell apoptosis and autophagy protein light chain 3B and Beclin-1, whereas these effects were reversed by different concentrations of N-acetyl-l-cysteine (NAC) posttreatment. In addition, NAC abolished H2O2-induced autophagic flux, inhibited intracellular and mitochondrial ROS, and restored expression of genes important for mitochondrial DNA and biogenesis, cell attachment, and differentiation. NAC reversed H2O2-activated MAPK and Akt/mammalian target of rapamycin pathways in dose-dependent manners. Furthermore, analyses with pharmacological and RNA interference approaches suggested that autophagy regulated cell apoptosis and gene expression of caudal-related homeobox 2 and IL-1ß. Collectively, these results provide new insights into the role of the ROS-induced autophagy in pTr cell apoptosis, attachment, and differentiation, indicating a promising target for decreasing porcine conceptus loss during the peri-implantation period.

Role and mechanism of ROS scavengers in alleviating NLRP3-mediated inflammation.

Inflammation, as a common immune response to various infections or injuries, can cause many dangerous and complicated diseases. Inflammasome is a protein complex playing a vital role in an inflammation process, and the nucleotide-binding oligomerization domain (NOD)-like receptor containing pyrin domain 3 (NLRP3) inflammasome has been the most-widely studied one. Recent evidence suggests the reactive oxygen species (ROS)-NLRP3 signaling pathway to be a possible NLRP3 inflammasome regulation model. Numerous recent preclinical reports indicate that application of antioxidants could scavenge excessive ROS and attenuate inflammatory responses through suppressing NLRP3 inflammasome activation. This article, at first, briefly overviews how ROS may mediate the regulation of NLRP3 inflammasome activation. Then, preclinical researches of various ROS scavengers for treating NLRP3 inflammasome-associated diseases are focused on and critically analyzed. Finally, the potential of antioxidant treatment as a therapy for inflammation is to be discussed, and perspectives on future research directions will be shared.

Localized, highly efficient secretion of signaling proteins by migrasomes.

Migrasomes, enriched with signaling molecules such as chemokines, cytokines and angiogenic factors, play a pivotal role in the spatially defined delivery of these molecules, influencing critical physiological processes including organ morphogenesis and angiogenesis. The mechanism governing the accumulation of signaling molecules in migrasomes has been elusive. In this study, we show that secretory proteins, including signaling proteins, are transported into migrasomes by secretory carriers via both the constitutive and regulated secretion pathways. During cell migration, a substantial portion of these carriers is redirected to the rear of the cell and actively transported into migrasomes, driven by the actin-dependent motor protein Myosin-5a. Once at the migrasomes, these carriers fuse with the migrasome membrane through SNARE-mediated mechanisms. Inhibiting migrasome formation significantly reduces secretion, suggesting migrasomes as a principal secretion route in migrating cells. Our findings reveal a specialized, highly localized secretion paradigm in migrating cells, conceptually paralleling the targeted neurotransmitter release observed in neuronal systems.

Inclusion of microbe-derived antioxidant during pregnancy and lactation attenuates high-fat diet-induced hepatic oxidative stress, lipid disorders, and NLRP3 inflammasome in mother rats and offspring.

OBJECTIVE: This study aimed to evaluate the effects of microbe-derived antioxidant (MA) on high-fat diet (HFD)-induced hepatic lipid disorders in mother rats and offspring. METHODS: A total of 36 female rats were randomly divided into three groups at the beginning of pregnancy: the control group (CG), HFD, and HFD with 2% MA. Mother rats were slaughtered at the first and 10th day of lactation (L1 and L10) and offspring were slaughtered at L10. The plasma and liver of mother rats, and liver of offspring were collected. RESULTS: The results showed that MA reversed HFD-induced activities of inducible nitric oxide synthase (iNOS) and antioxidative enzymes in liver of mother rats and offspring. In addition, MA reduced HFD-induced lipid accumulation through decreasing the low-density lipoprotein cholesterol (LDLC) content in plasma of mother rats and improving hepatic fatty acid synthase (FAS) in mother rats and offspring. MA decreased HFD-induced hepatic alkaline phosphatase (AKP) activity in liver of mother rats and offspring. Furthermore, MA reduced HFD-activated nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome in liver of mother rats and offspring. CONCLUSIONS: MA supplementation reversed HFD-induced hepatic oxidative stress, lipid accumulation, NLRP3 inflammasome, and function in mother rats and offspring, suggesting MA can be functional ingredients to improve maternal-fetal health.

Effects of n-acetyl-cysteine supplementation in late gestational diet on maternal-placental redox status, placental NLRP3 inflammasome, and fecal microbiota in sows1.

Although n-acetyl-cysteine (NAC) has been shown to efficiently alleviate oxidative stress, inflammatory response, and alter gut microbiota, little attention has been focused on their interactions with placental metabolic status of sows. The effects of NAC on the placental redox status, function, inflammasome, and fecal microbiota in sows were explored to clarify the correlation between the fecal microbiota and placenta. Sows were divided into either the control group or the NAC group which received dietary 0.5% NAC supplementation from day 85 of gestation to delivery. Plasma redox status, placental growth factors, nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome, fecal microbial metabolites, and communities were evaluated. Compared with the control group, although NAC did not ameliorate reproductive performance of sows (P > 0.05), it significantly improved maternal-placental health, which was accompanied by increased activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD), decreased level of malondialdehyde (MDA), and lowered expression of interleukin (IL)-1ß and IL-18 through inhibiting NLRP3 inflammasome (P < 0.05). Additionally, NAC significantly increased placental insulin-like growth factors (IGFs) and E-cadherin contents (P < 0.05), elevated the expression of genes involved in angiogenesis and amino acids transporters (P < 0.05), and decreased the microtubule-associated protein light chain 3B (LC3B) and Beclin-1 protein expression (P < 0.05). Furthermore, NAC increased the relative abundances of fecal Prevotella, Clostridium cluster XIVa, and Roseburial/Eubacterium rectale (P < 0.05), which were negatively correlated with placental NLRP3 and positively with solute carrier family 7, member 8 (Slc7a8; P < 0.05). In conclusion, NAC supplementation during late gestation alleviated maternal-placental oxidative stress and inflammatory response, improved placental function, and altered fecal microbial communities.

Reactive oxygen species mediated placental oxidative stress, mitochondrial content, and cell cycle progression through mitogen-activated protein kinases in intrauterine growth restricted pigs.

Intrauterine growth restriction (IUGR) remains a significant obstacle in pig production; however, information regarding the relationship between reactive oxygen species (ROS)-induced placental dysfunction and IUGR is still unknown. This study aimed to explore the placental redox status, mitochondrial content, cellular progression, and mitogen-activated protein kinase (MAPK) pathways in IUGR. Placental tissues were collected from normal intrauterine gestation (NIUG) and IUGR fetuses at delivery. Compared with the NIUG, placental ROS production, lipid peroxidation, and DNA damage were increased in IUGR. Placental mitochondrial DNA (mtDNA) content and mtDNA-encoded gene expression decreased in IUGR. Moreover, p21 phosphorylation increased, cyclin E expression decreased in IUGR cases, which showed senescence characteristics. Analysis of signaling pathways showed that the ERK1/2 phosphorylation increased whereas the p38 and JNK phosphorylation decreased in IUGR. In cultured porcine trophectoderm (pTr) cells, exogenous H2O2 increased intracellular ROS production, decreased cell viability in a dose-dependent manner. Cell cycle distribution was found to arrest in S and G2/M phases. Our findings suggested that IUGR was associated with greater placental ROS and oxidative injury, which might be a factor that resulted in lower mitochondrial content, microvilli loss and senescence, and activation of MAPK pathways.