Formation Of Lysosomes Research Articles

TMBIM6 (transmembrane BAX inhibitor motif containing 6) enhances autophagy and reduces renal dysfunction in a cyclosporine A-induced nephrotoxicity model

Cyclosporine A (CsA) is widely used as an immunosuppressor in transplantation. Previous studies reported that CsA induces autophagy and that chronic treatment with CsA results in accumulation of autophagosomes and reduced autophagic clearance. Autophagy is a prosurvival process that promotes recovery from acute kidney injury by degrading misfolded proteins produced in the kidney. In the present study, we used TMBIM6-expressing HK-2, human kidney tubular cells (TMBIM6 cells) and Tmbim6 knockout (tmbim6−/−) mice. When exposed to CsA, the TMBIM6 cells maintained autophagy activity by preventing autophagosome accumulation. With regard to signaling, PRKKA/AMPK phosphorylation and mechanistic target of rapamycin (serine/threonine kinase) complex 1 (MTORC1) expression and its downstream target TFEB (transcription factor EB), a lysosome biogenesis factor, were regulated in the TMBIM6 cells. Lysosomal activity was highly increased or stably maintained in the presence of TMBIM6. In addition, treatment of tmbim6−/− mice with CsA resulted in increased autophagosome formation and decreased lysosome formation and activity. We also found that tmbim6−/− mice were susceptible to CsA-induced kidney injury. Taken together, these results indicate that TMBIM6 protects against CsA-induced nephrotoxicity both in vitro and in vivo by inducing autophagy and activating lysosomes.

ASSESSMENT OF Fe2O3 NANOPARTICLES IMPACT ON FUNCTIONAL ACTIVITY OF RATS’ PERITONEAL MACROPHAGES IN EXPERIMENTS IN VITRO AND IN VIVO

Introduction.Today much attention is paid in the world to studying safety of nanomaterials (NM), which are synthesized and used in different spheres of human activity. Among metallic nanoparticles (NPs), iron and iron oxides are widely used in medicine and pharmacy. An important step in learning, how NPs affect living organisms, is studying their toxicity and biological activity. Macrophages are of a particular interest in this respect, which are available in various tissues and which are key cells in forming an immune response. Purpose of the study. To assess Fe 2O3 NPs influence on viability and functional activity of peritoneal macrophages in rats in experiments in vitroand in vivo. Materials and methods. Fe 2O3 NPs of 19 nm and 75 nm were obtained by chemical methods. The viability of peritoneal macrophages under the influence of Fe 2O3 NPs of 19 nm and 75 nm was defined by trypan blue and MTT test; the phagocytic activity was assessed by absorption of latex particles and cytochemically; bactericidity – by NBT-test. Results. The studies showed that incubation of macrophages with NPs in vitrocaused death of 30 % cells, whereas entering NPs into the body in vivohad no effect on their viability. NPs activated macrophage phagocytosis, formation of large phagocytic vacuoles, fagosom, lysosomes and fagolizosom as well as production of reactive oxygen forms. NPs activity depends on their size and conditions of experiments.

Para-toluenesulfonamide induces tongue squamous cell carcinoma cell death through disturbing lysosomal stability.

Para-toluenesulfonamide (PTS) has been implicated with anticancer effects against a variety of tumors. In the present study, we investigated the inhibitory effects of PTS on tongue squamous cell carcinoma (Tca-8113) and explored the lysosomal and mitochondrial changes after PTS treatment in vitro. High-performance liquid chromatography showed that PTS selectively accumulated in Tca-8113 cells with a relatively low concentration in normal fibroblasts. Next, the effects of PTS on cell viability, invasion, and cell death were determined. PTS significantly inhibited Tca-8113 cells’ viability and invasive ability with increased cancer cell death. Flow cytometric analysis and the lactate dehydrogenase release assay showed that PTS induced cancer cell death by activating apoptosis and necrosis simultaneously. Morphological changes, such as cellular shrinkage, nuclear condensation as well as formation of apoptotic body and secondary lysosomes, were observed, indicating that PTS might induce cell death through disturbing lysosomal stability. Lysosomal integrity assay and western blot showed that PTS increased lysosomal membrane permeabilization associated with activation of lysosomal cathepsin B. Finally, PTS was shown to inhibit ATP biosynthesis and induce the release of mitochondrial cytochrome c. Therefore, our findings provide a novel insight into the use of PTS in cancer therapy.

Effects of Graphene Oxide and Oxidized Carbon Nanotubes on the Cellular Division, Microstructure, Uptake, Oxidative Stress, and Metabolic Profiles.

Nanomaterial oxides are common formations of nanomaterials in the natural environment. Herein, the nanotoxicology of typical graphene oxide (GO) and carboxyl single-walled carbon nanotubes (C-SWCNT) was compared. The results showed that cell division of Chlorella vulgaris was promoted at 24 h and then inhibited at 96 h after nanomaterial exposure. At 96 h, GO and C-SWCNT inhibited the rates of cell division by 0.08-15% and 0.8-28.3%, respectively. Both GO and C-SWCNT covered the cell surface, but the uptake percentage of C-SWCNT was 2-fold higher than that of GO. C-SWCNT induced stronger plasmolysis and mitochondrial membrane potential loss and decreased the cell viability to a greater extent than GO. Moreover, C-SWCNT-exposed cells exhibited more starch grains and lysosome formation and higher reactive oxygen species (ROS) levels than GO-exposed cells. Metabolomics analysis revealed significant differences in the metabolic profiles among the control, C-SWCNT and GO groups. The metabolisms of alkanes, lysine, octadecadienoic acid and valine was associated with ROS and could be considered as new biomarkers of ROS. The nanotoxicological mechanisms involved the inhibition of fatty acid, amino acid and small molecule acid metabolisms. These findings provide new insights into the effects of GO and C-SWCNT on cellular responses.

P2X7 Receptor Regulates Internalization of Antimicrobial Peptide LL-37 by Human Macrophages That Promotes Intracellular Pathogen Clearance.

Bioactive peptide LL-37/hCAP18, the only human member of the cathelicidin family, plays important roles in killing various pathogens, as well as in immune modulation. We demonstrate that LL-37 is internalized by human macrophages in a time-, dose-, temperature-, and peptide sequence-dependent endocytotic process. Both clathrin- and caveolae/lipid raft-mediated endocytosis pathways are involved in LL-37 internalization. We find that the P2X7 receptor (P2X7R) plays an important role in LL-37 internalization by human macrophages because significantly less internalized LL-37 was detected in macrophages pretreated with P2X7R antagonists or, more specifically, in differentiated THP-1 cells in which the P2X7R gene had been silenced. Furthermore, this P2X7R-mediated LL-37 internalization is primarily connected to the clathrin-mediated endocytosis pathway. In addition, our results demonstrate that internalized LL-37 traffics to endosomes and lysosomes and contributes to intracellular clearance of bacteria by human macrophages, coinciding with increased reactive oxygen species and lysosome formation. Finally, we show that human macrophages have the potential to import LL-37 released from activated human neutrophils. In conclusion, our study unveils a novel mechanism by which human macrophages internalize antimicrobial peptides to improve their intracellular pathogen clearance.

Cellular repressor of E1A-stimulated genes inhibits inflammation to decrease atherosclerosis in ApoE−/− mice

AimsMacrophage inflammation response is important in the pathogenesis of atherosclerosis. We investigated the role and mechanism of cellular repressor of E1A-stimulated genes (CREG) in regulating TNF-α induced inflammation response in macrophages and explore whether CREG might be a therapeutic target for atherosclerosis. Method and resultsImmunostaining and western blotting showed that expression of CREG was reduced in human atherosclerotic coronary artery. In vivo experiments demonstrated that supplementation of recombinant CREG protein to ApoE−/− mice fed with high fat diet alleviated aortic atherosclerosis development and inflammation. In vitro, macrophage from ApoE−/− mice fed with high fat diet had lower level of CREG compared to control mice fed with normal diet. Immunohistochemical staining and western blotting further confirmed that CREG inhibited inflammatory response of macrophages induced by TNF-α. Supplementation of exogenous recombinant CREG protein or CREG gene silencing showed that CREG promoted autophagy in TNF-α treated macrophages. The use of autophagy inhibitors, 3-methyladenine and bafilomycin A, identified that CREG attenuated TNF-α induced inflammation by activate autophagy. In addition, supplementation of exogenous CREG protein stimulated expression and maturity of cathepsin B and cathepsin L and induced lysosome formation, whereas CREG deficiency reduced lysosomal formation. ConclusionCREG inhibits inflammation and promotes autophagy mediated by lysosome formation; it might be a potential therapeutic target in atherosclerosis.

Uptake, metabolism and toxicity of iron oxide nanoparticles in cultured microglia, astrocytes and neurons

Iron oxide nanoparticles (IONPs) are frequently used for biomedical applications including magnetic resonance imaging, drug delivery or tumor treatment by hyperthermia. Since IONPs can reach the brain from periphery or are directly applied into the brain, the investigation of potential adverse effects of IONPs on properties and functions of the different types of brain cells is an important task. In order to directly compare different types of brain cells concerning the uptake and toxicity of IONPs, we synthesized fluorescent IONPs and characterized these BODIPY-labeled particles regarding their physicochemical properties. In the medium used for the cell studies, these particles had a hydrodynamic diameter of around 158 ± 28 nm and a negative surface charge with a zeta-potential of -10 ± 2 mV. Exposure of primary cultures of rat astrocytes, neurons and microglial cells revealed that among these cell types, microglial cells accumulated IONPs most rapidly. However, microglial cells were also most vulnerable towards acute IONP-induced stress while astrocytes and neurons were not acutely damaged by IONPs. In microglial cells, but not in astrocytes or neurons, IONPs were found to be localized in lysosomes and large amounts of reactive oxygen species (ROS) were observed after IONP-exposure. The IONP-induced toxicity in microglial cells was prevented by neutralizing lysosomes or by chelation of intracellular ferrous iron ions, suggesting that the toxic potential of IONPs in microglia involves rapid particle uptake, liberation of ferrous iron from the internalized IONPs in the acidic lysosomal compartment and iron-catalyzed ROS formation. These data suggest that also in brain IONPs may harm microglial cells and compromise microglial functions.

Lysosomes are involved in induction of steroidogenic acute regulatory protein (StAR) gene expression and progesterone synthesis through low-density lipoprotein in cultured bovine granulosa cells

Progesterone is an important steroid hormone in the regulation of the bovine estrous cycle. The steroidogenic acute regulatory protein (StAR) is an indispensable component for transporting cholesterol to the inner mitochondrial membrane, which is one of the rate-limiting steps for progesterone synthesis. Low-density lipoprotein (LDL) supplies cholesterol precursors for progesterone formation, and the lysosomal degradation pathway of LDL is essential for progesterone biosynthesis in granulosa cells after ovulation. However, it is currently unknown how LDL and lysosomes coordinate the expression of the StAR gene and progesterone production in bovine granulosa cells. Here, we investigated the role of lysosomes in LDL-treated bovine granulosa cells. Our results reported that LDL induced expression of StAR messenger RNA and protein as well as expression of cholesterol side-chain cleavage cytochrome P-450 (CYP11A1) messenger RNA and progesterone production in cultured bovine granulosa cells. The number of lysosomes in the granulosa cells was also significantly increased by LDL; whereas the lysosomal inhibitor, chloroquine, strikingly abolished these LDL-induced effects. Our results indicate that LDL promotes StAR expression, synthesis of progesterone, and formation of lysosomes in bovine granulosa cells, and lysosomes participate in the process by releasing free cholesterol from hydrolyzed LDL.

Mucolipidosis type IV protein TRPML1-dependent lysosome formation.

Lysosomes are dynamic organelles that undergo cycles of fusion and fission with themselves and with other organelles. Following fusion with late endosomes to form hybrid organelles, lysosomes are reformed as discrete organelles. This lysosome reformation or formation is a poorly understood process that has not been systematically analyzed and that lacks known regulators. In this study, we quantitatively define the multiple steps of lysosome formation and identify the first regulator of this process.

Autophagy facilitates secretion and protects against degeneration of the Harderian gland

The epithelial derived Harderian gland consists of 2 types of secretory cells. The more numerous type A cells are responsible for the secretion of lipid droplets, while type B cells produce dark granules of multilamellar bodies. The process of autophagy is constitutively active in the Harderian gland, as confirmed by our analysis of LC3 processing in GFP-LC3 transgenic mice. This process is compromised by epithelial deletion of Atg7. Morphologically, the Atg7 mutant glands are hypotrophic and degenerated, with highly vacuolated cells and pyknotic nuclei. The mutant glands accumulate lipid droplets coated with PLIN2 (perilipin 2) and contain deposits of cholesterol, ubiquitinated proteins, SQSTM1/p62 (sequestosome 1) positive aggregates and other metabolic products such as porphyrin. Immunofluorescence stainings show that distinct cells strongly aggregate both proteins and lipids. Electron microscopy of the Harderian glands reveals that its organized structure is compromised, and the presence of large intracellular lipid droplets and heterologous aggregates. We attribute the occurrence of large vacuoles to a malfunction in the formation of multilamellar bodies found in the less abundant type B Harderian gland cells. This defect causes the formation of large tertiary lysosomes of heterologous content and is accompanied by the generation of tight lamellar stacks of endoplasmic reticulum in a pseudo-crystalline form. To test the hypothesis that lipid and protein accumulation is the cause for the degeneration in autophagy-deficient Harderian glands, epithelial cells were treated with a combination of the proteasome inhibitor and free fatty acids, to induce aggregation of misfolded proteins and lipid accumulation, respectively. The results show that lipid accumulation indeed enhanced the toxicity of misfolded proteins and that this was even more pronounced in autophagy-deficient cells. Thus, we conclude autophagy controls protein and lipid catabolism and anabolism to facilitate bulk production of secretory vesicles of the Harderian gland.

Suppression of influenza A virus replication in human lung epithelial cells by noncytotoxic concentrations bafilomycin A1.

Subcellular trafficking within host cells plays a critical role in viral life cycles, including influenza A virus (IAV). Thus targeting relevant subcellular compartments holds promise for effective intervention to control the impact of influenza infection. Bafilomycin A1 (Baf-A1), when used at relative high concentrations (≥10 nM), inhibits vacuolar ATPase (V-ATPase) and reduces endosome acidification and lysosome number, thus inhibiting IAV replication but promoting host cell cytotoxicity. We tested the hypothesis that much lower doses of Baf-A1 also have anti-IAV activity, but without toxic effects. Thus we assessed the antiviral activity of Baf-A1 at different concentrations (0.1-100 nM) in human alveolar epithelial cells (A549) infected with IAV strain A/PR/8/34 virus (H1N1). Infected and mock-infected cells pre- and cotreated with Baf-A1 were harvested 0-24 h postinfection and analyzed by immunoblotting, immunofluorescence, and confocal and electron microscopy. We found that Baf-A1 had disparate concentration-dependent effects on subcellular organelles and suppressed affected IAV replication. At concentrations ≥10 nM Baf-A1 inhibited acid lysosome formation, which resulted in greatly reduced IAV replication and release. Notably, at a very low concentration of 0.1 nM that is insufficient to reduce lysosome number, Baf-A1 retained the capacity to significantly impair IAV nuclear accumulation as well as IAV replication and release. In contrast to the effects of high concentrations of Baf-A1, very low concentrations did not exhibit cytotoxic effects or induce apoptotic cell death, based on morphological and FACS analyses. In conclusion, our results reveal that low-concentration Baf-A1 is an effective inhibitor of IAV replication, without impacting host cell viability.

Mitophagy of damaged mitochondria occurs locally in distal neuronal axons and requires PINK1 and Parkin.

To minimize oxidative damage to the cell, malfunctioning mitochondria need to be removed by mitophagy. In neuronal axons, mitochondrial damage may occur in distal regions, far from the soma where most lysosomal degradation is thought to occur. In this paper, we report that PINK1 and Parkin, two Parkinson's disease-associated proteins, mediate local mitophagy of dysfunctional mitochondria in neuronal axons. To reduce cytotoxicity and mimic physiological levels of mitochondrial damage, we selectively damaged a subset of mitochondria in hippocampal axons. Parkin was rapidly recruited to damaged mitochondria in axons followed by formation of LC3-positive autophagosomes and LAMP1-positive lysosomes. In PINK1(-/-) axons, damaged mitochondria did not accumulate Parkin and failed to be engulfed in autophagosomes. Similarly, initiation of mitophagy was blocked in Parkin(-/-) axons. Our findings demonstrate that the PINK1-Parkin-mediated pathway is required for local mitophagy in distal axons in response to focal damage. Local mitophagy likely provides rapid neuroprotection against oxidative stress without a requirement for retrograde transport to the soma.

Endothelial Cell Heparanase Taken Up by Cardiomyocytes Regulates Lipoprotein Lipase Transfer to the Coronary Lumen After Diabetes

After diabetes, the heart has a singular reliance on fatty acid (FA) for energy production, which is achieved by increased coronary lipoprotein lipase (LPL) that breaks down circulating triglycerides. Coronary LPL originates from cardiomyocytes, and to translocate to the vascular lumen, the enzyme requires liberation from myocyte surface heparan sulfate proteoglycans (HSPGs), an activity that needs to be sustained after chronic hyperglycemia. We investigated the mechanism by which endothelial cells (EC) and cardiomyocytes operate together to enable continuous translocation of LPL after diabetes. EC were cocultured with myocytes, exposed to high glucose, and uptake of endothelial heparanase into myocytes was determined. Upon uptake, the effect of nuclear entry of heparanase was also investigated. A streptozotocin model of diabetes was used to expand our in vitro observations. In high glucose, EC-derived latent heparanase was taken up by cardiomyocytes by a caveolae-dependent pathway using HSPGs. This latent heparanase was converted into an active form in myocyte lysosomes, entered the nucleus, and upregulated gene expression of matrix metalloproteinase-9. The net effect was increased shedding of HSPGs from the myocyte surface, releasing LPL for its onwards translocation to the coronary lumen. EC-derived heparanase regulates the ability of the cardiomyocyte to send LPL to the coronary lumen. This adaptation, although acutely beneficial, could be catastrophic chronically because excess FA causes lipotoxicity. Inhibiting heparanase function could offer a new strategy for managing cardiomyopathy observed after diabetes.

Src-dependent impairment of autophagy by oxidative stress in a mouse model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a fatal degenerative muscle disease resulting from mutations in the dystrophin gene. Increased oxidative stress and altered Ca2+ homeostasis are hallmarks of dystrophic muscle. While impaired autophagy has recently been implicated in the disease process, the mechanisms underlying the impairment have not been elucidated. Here we show that nicotinamide adenine dinucleotide phosphatase (Nox2)-induced oxidative stress impairs both autophagy and lysosome formation in mdx mice. Persistent activation of Src kinase leads to activation of the autophagy repressor mammalian target of rapamycin (mTOR) via PI3K/Akt phosphorylation. Inhibition of Nox2 or Src kinase reduces oxidative stress and partially rescues the defective autophagy and lysosome biogenesis. Genetic down regulation of Nox2 activity in the mdx mouse decreases ROS production, abrogates defective autophagy and rescues histological abnormalities and contractile impairment. Our data highlight mechanisms underlying the pathogenesis of DMD and identify NADPH oxidase and Src kinase as potential therapeutic targets.

Challenging the roles of CD44 and lipolysis stimulated lipoprotein receptor in conveying Clostridium perfringens iota toxin cytotoxicity in breast cancer.

BackgroundTranslational exploration of bacterial toxins has come to the forefront of research given their potential as a chemotherapeutic tool. Studies in select tissues have demonstrated that Clostridium perfringens iota toxin binds to CD44 and lipolysis stimulated lipoprotein receptor (LSR) cell-surface proteins. We recently demonstrated that LSR expression correlates with estrogen receptor positive breast cancers and that LSR signaling directs aggressive, tumor-initiating cell behaviors. Herein, we identify the mechanisms of iota toxin cytotoxicity in a tissue-specific, breast cancer model with the ultimate goal of laying the foundation for using iota toxin as a targeted breast cancer therapy.MethodsIn vitro model systems were used to determine the cytotoxic effect of iota toxin on breast cancer intrinsic subtypes. The use of overexpression and knockdown technologies confirmed the roles of LSR and CD44 in regulating iota toxin endocytosis and induction of cell death. Lastly, cytotoxicity assays were used to demonstrate the effect of iota toxin on a validated set of tamoxifen resistant breast cancer cell lines.ResultsTreatment of 14 breast cancer cell lines revealed that LSR+/CD44- lines were highly sensitive, LSR+/CD44+ lines were slightly sensitive, and LSR-/CD44+ lines were resistant to iota cytotoxicity. Reduction in LSR expression resulted in a significant decrease in toxin sensitivity; however, overexpression of CD44 conveyed toxin resistance. CD44 overexpression was correlated with decreased toxin-stimulated lysosome formation and decreased cytosolic levels of iota toxin. These findings indicated that expression of CD44 drives iota toxin resistance through inhibition of endocytosis in breast cancer cells, a role not previously defined for CD44. Moreover, tamoxifen-resistant breast cancer cells exhibited robust expression of LSR and were highly sensitive to iota-induced cytotoxicity.ConclusionsCollectively, these data are the first to show that iota toxin has the potential to be an effective, targeted therapy for breast cancer.

Activation of lysosomal degradative pathway in spinal cord tissues of carbon disulfide-treated rats

Chronic exposure to carbon disulfide (CS2) can induce polyneuropathy in occupational worker and experimental animals, but underlying mechanism for CS2 neuropathy is currently unknown. In the present study, male Wistar rats were randomly divided into three experimental groups and one control group. The rats in experimental groups were treated with CS2 by gavage at dosages of 200, 400 and 600mg/kg/day respectively, six times per week for 6weeks. The formation of autophagosomes and lysosomes in motor neurons of rat spinal cord was observed by transmission electron microscopy, the level of autophagy-related proteins, lysosome-associated membrane protein 1 (LAMP-1), and cathepsin B in spinal cord tissues was determined by Western blot analysis, and the activity of cathepsin B was measured by fluorescence assay. The results demonstrated that the number of lysosomes in motor neurons was markedly increased in CS2-treated rats. In the meantime, the administration of CS2 significantly increased the level of microtubule-associated protein light chain 3-II (LC3-II), Atg1, UVRAG and LAMP-1 in rat spinal cord. Furthermore, the content and activity of cathepsin B in rat spinal cord also showed a significant elevation. Taken together, this study suggested that CS2 intoxication was associated with the activation of lysosomal degradative machinery, which might play a protective role against CS2-induced neuronal damage.

Immunomodulatory Action of Triterpene Glycosides Isolated from the Sea Cucumber Actinocucumis typica. Structure-Activity Relationships

Stimulation of lysosomal activity and ROS formation in mouse peritoneal macrophages by five triterpene glycosides, typicosides A1 (1), A2 (2), B1 (3), C1 (4) and C2 (5) has been studied and compared with their cytotoxic activities. Glycosides 1-3 possess moderate activities, but the most cytotoxic glycoside 5 is not active. Typicoside C1 (4), with low toxicity, was proved to be the most active concerning stimulation of ROS formation. This is the first example of a triterpene glycoside from sea cucumbers with low cytotoxicity, but which demonstrates a strong immunostimulatory effect on mouse peritoneal macrophages in vitro.

Chaetal loss and replacement in Pseudopotamilla reniformis (Sabellida, Annelida)

AbstractChaetae are continually being replaced during the life of a polychaete, but the process of chaetal degeneration during replacement is still poorly known. Chaetal loss occurs either one at a time through special degenerative sites, or all chaetae in a chaetal sac are lost simultaneously in the absence of degenerative sites. Old chaetae can be either resorbed inside the coelom or shed. This study describes chaetal degradation, loss, and subsequent replacement during experimentally induced regeneration in the sabellid polychaete Pseudopotamilla reniformis. During post‐traumatic regeneration in P. reniformis, abdominal‐type chaetae fall from the chaetal sac simultaneously without degenerative sites, and are replaced by thoracic‐type chaetae. Chaetal sac degradation occurs in three main stages: (1) formation of numerous lysosomes and small electron‐transparent vesicles in follicle cell cytoplasm; (2) disintegration of follicular cell membranes; and (3) disintegration of follicular cell cytoplasm. Description of changes during parapodial transformation allows identification of signs of degradation that can serve as histological indicators of chaetal degeneration in a wide range of polychaetes. Our study suggests that chaetal degeneration and loss in polychaetes can occur either with degenerative sites or without them, depending on the type of chaetal replacement.

Atg5 deficit exaggerates the lysosome formation and cathepsin B activation in mice brain after lipid nanoparticles injection

The present study was designed to investigate the role of autophagy-lysosome signaling in the brain after application of nanoparticles. Here, lipid nanoparticles (LNs) induced elevations of Atg5, P62, LC3 and cathepsin B in mice brain. The transmission electron microscopy revealed a dramatic elevation of lysosome vacuoles colocalized with LNs cluster inside the neurons in mice brain. Immunoblot data revealed abnormal expression of cathepsin B in brain cortex following LNs injection, whereas its expression was further elevated in Atg5+/− mice. The importance of Atg5 in the LNs-induced autophagy-lysosome cascade was further supported by our finding that neurovascular response was exaggerated in Atg5+/− mice. In addition, the siRNA knockdown of Atg5 significantly blunted the increasing of LC3 and P62 in LNs-treated Neuro-2a cells. Taken together, we propose that LNs induce autophagy-lysosome signaling and neurovascular response at least partially via an Atg5-dependent pathway. From the Clinical EditorThese authors investigated autophagy-lysosome signaling in the mouse brain after application of lipid nanoparticles and report that these nanoparticles induce autophagy-lysosome signaling and neurovascular response at least partially via an Atg5-dependent pathway.

Changes in the synganglion of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) female ticks exposed to permethrin: An ultrastructural overview

This study performed the ultra-structural analysis of the changes caused by permethrin in the synganglion of semi-engorged Rhipicephalus sanguineus females, aiming to understand the toxic action of this substance at cellular level. The results showed that the neural lamella had its structure changed, allowing the influx of the toxic agent into the nervous tissue. The glial cells of the perineurium, as well as the neural cells of the cortex showed great changes, such as: irregular nuclei with chromatin margination, cytoplasmic vacuolation and degenerating mitochondria. These changes showed that the permethrin would be able to induce the degeneration of the synganglion through an atypical death process, involving apoptosis and autophagy. In addition, a dilated rough endoplasmic reticulum was observed in the neural cells, suggesting an intense synthesis of the hydrolytic enzymes that would be used in the processes of degradation of the damaged cellular structures (formation of lysosomes). The subperineurium and the neuropile also showed changes in their structures. Thus, it is suggested that permethrin is a dose-dependent compound able to impair the metabolism of the organism as a whole, once all the other organs and body structures are directly dependent of the neural control. The information obtained in this study can be used in the improvement of the control methods which use permethrin as active substance, helping in the creation of a really efficient acaricide product to fight this important urban plague.